style-guide.md

Raspberry Pi style guide

This document is being updated constantly; please ensure you have the most recent version.

When preparing copy for UK or international audiences (that is, the vast majority of our content), unless the matter is mentioned below, please consult New Hart's Rules: The Oxford Guide to Style. If a particular spelling or hyphenation choice is not specified here, the version in the Oxford English Dictionary is to be preferred.

When editing copy that is intended specifically for a US audience, refer to the Associated Press Stylebook.

Raspberry Pi strives for an approachable, conversational tone in its materials. See www.raspberrypi.com for examples.

Lists

Use semicolons for lists with internal commas. We received bouquets from Chris, in California; Jim, in Belgium; and Bob, in Liverpool.

Complicated lists are usually better presented typographically with bullets or numerals, but don't resort to bulleted lists just because it's the easiest option: consider narrative flow and page layout. Bullets should be used for lists of items with no hierarchy, numerals for lists of items with hierarchy, and for steps in a process (for example tutorials). Letters should never be used for list points. Bullet points take a capital letter but do not take a full stop (this includes the final list item) unless one or more of the bulleted list items is made up of more than one sentence, in which case all points on the list should have a full stop, even if they are fragments.

A bulleted list should be introduced with a colon:

• First list item
• Second list item
• Third list item

See Titles of other works below for more examples of bulleted lists.

Emphasis

Use italic type for emphasis. Note: this is a change to reflect our normal usage. We used to prefer bold type for emphasis, but it's clear that it's not what writers and editors here default to, so italics win (and we've used bold so little for emphasis that there's little point in going back through and retroactively mopping up).

Punctuation

Oxford commas should be used throughout; they resolve ambiguity and should be used elsewhere for consistency. We photographed the components, a sandwich, and a magnet.

Do you find yourself adding more and more commas to make your sentence readable? Perhaps it would be better if you split it into two sentences instead. That said, at Raspberry Pi we're committed to railing against the death of the semicolon; it's a very useful piece of punctuation.

Hyphen (-):

In general,

• Hyphenate two or more modifiers before a noun unless the first modifier is an adjective that modifies the complete noun phrase. The moderators are fascist-robot enthusiasts. The moderators are fascist robot enthusiasts.
• Compound nouns that are used as a modifier before a noun need not always be hyphenated; if a hyphen makes them look stuffy and old-fashioned, leave it out. Machine vision applications, science fiction titles, labour market liberalisation.
• Do not hyphenate compound modifiers that follow a noun. We try to make sure our advice on hyphenation remains up to date (but What's a good channel for up-to-date advice on home fungiculture?)
• Do not hyphenate adjectival compounds which begin with adverbs ending -ly. A gorgeously constructed computer.
• Add a hyphen on the end of multiple items that are joined to another word in this way. A 12- and 15-month subscription, full- and part-time jobs.
• Consult en dash rules for more complex hyphenation cases.
• Consult Hart's Rules for more complex hyphenation cases where the en dash rules aren't helping you out.

En dash (–):

• Use a closed-up en dash when writing ranges. 7–17, Monday–Friday.
• Use a closed-up en dash when expressing a connection, relation, or alternative. Dover–Calais crossing, Williams–Navratilova match.
• Use a closed-up en dash to form compound words either when one of the components is itself a hyphenated word, or when one of the components is formed of two words. Raspberry Pi–powered, e-book–only publisher, public school–educated student, liberal–conservative debate.

Em dash (—):

• Use an em dash with space either side for parenthetical statements. Em dashes express a more pronounced break in the sentence than commas, and also draw more attention to the parenthetical. They express less of a break than parentheses, and are more informal. Do not overuse em dashes. I didn't have an educated background — Dad was a farm labourer.
• Use a pair of em dashes with space either side for making a parenthetical statement in the middle of a sentence. If using punctuation in the parenthetical, the closing dash may only be preceded by an exclamation or question mark and the following word may not be capitalised, even if it begins a sentence (unless it is a proper noun). E.g. The party lasted — we knew it would! — far longer than planned.

Colon:

• When a colon is used in free text, the letter following the colon should be lower-case. E.g. I have three dogs: a small one, a medium one, and a big one.
• When a colon is preceded by a header-style construction, the letter following the colon should be upper-case. E.g. Note: This wouldn’t look so great with a lower-case t.

Quotation marks (' and "):

• Do not use scare quotes (quotation marks put around a word or phrase in a written sentence in order to show that the word is being used in a special way, or in a way that may not be correct or true). Scare quotes make for vague, sensationalist writing. You can write better than that.
• Use single quotes to highlight a word/phrase when needed, such as when you introduce a new term, need to offset a title. E.g. Ask what the word 'system' means. or Hand out the ‘Bicycle system’ activity sheet.
• Be judicious in your use of quotation marks in this way: if the word/phrase stands out to the reader without them, leave them out; if the reader might stumble over the word/phrase without them, put them in.
• Use double quotation marks only to indicate actual quoted speech.
• In large sections of quoted speech, put double quotation marks at the end of each paragraph rather than omitting them, as per the Oxford Guide to Style.

Fragments (e.g. for definitions) do not take a full stop at the end. An isolated or incomplete part of something

Do not use apostrophes in abbreviated plurals: PCs, BGAs. Apostrophes may be used when an abbreviation is turned into a verb, although it is best practice to avoid doing this altogether: My mother won't stop IM'ing me. (This example is from the deep past, when mothers IM'd. Now they WhatsApp us.)

Do not use ampersands (&); always use 'and'. The exception might be in a print article for one of our magazines, where space is at a premium.

Titles of other works

Titles of other works should be set in title case (first and last words take an initial capital, regardless of length of word or part of speech; all other words in the title except articles, prepositions of three or fewer letters and conjunctions of three or fewer letters, and the words if, how and why should also take an initial capital.)

As a general rule with software in particular, check the manufacturer's capitalisation style. Many examples of software title capitalisation are in the word list below; if you encounter more that you think we add, please start a pull request.

Treatment of the titles depends on the type of work. In general, titles should be set in italics.

Italicise the titles of the following types of works: artworks; books, book chapters and other parts of books; CDs; albums; DVDs; songs; lectures; magazine and newspaper articles; films; operas; plays; podcasts and episodes of podcasts; poems; speeches with titles; television and radio programmes and episodes; web shows; webinars; and online videos.

Do not italicise titles if they fall under one of the following categories:

• Blogs. The titles of individual blog posts should be set in italics (unless the blog publishes posts under a date only).
• Games. Computer games, board games, card games, arcade games.
• Magazines and newspapers. The titles of specific articles from magazines and newspapers should, however, be set in italics.
• Websites.
• Software.

But wait! There's more!

If compiling a numbered or bulleted list of titles which are like items, the titles do not need to be set in italics because they do not need to stand out from surrounding text. A similar list of titles which are not like items should be set in italics where they are required.

Jemima's favourite old movies are:

• Gone With the Wind
• Singin' in the Rain
• The Third Man

These are a few of my favourite things:

• Sausages
• Banditry
• Anne of Green Gables

Raspberry Pi computers, microcontroller devices, microcontroller boards, and camera modules

Are you talking about Raspberry Pi the concept, or about a specific Raspberry Pi? If you're writing about the product line, then "Raspberry Pi 4", "Raspberry Pi Zero", "Raspberry Pi Pico", "Raspberry Pi Camera Module 2", and so on; not "the Raspberry Pi 4" or "the Raspberry Pi Zero", and not just "Pi 4" or "Pi Zero".

If you're writing about a specific Raspberry Pi: one your reader is using in a project, or the one you're holding in your hand, use the appropriate article. "Pick up a Raspberry Pi." "Insert a microSD card into your Raspberry Pi." "Mount the HAT on the Raspberry Pi." Helen, as instructed, I'm leaving a note in here to get you to unclench. Sometimes an article might be better used where we might not use one according to the strict terms of this document for reasons of flow and readability. Exercise stylistic judgment!

The plural of "Raspberry Pi" is "Raspberry Pis" (no apostrophe); but use "Raspberry Pi computers", "Raspberry Pi devices", etc. where possible.

To check official nomenclature, refer to the Product Names Register on Cognidox internally, or the products page.

Be careful with using Raspberry Pi 1 — the 1 is only necessary when you need to clearly distinguish it from other models. If you want to shorten the name of a model, do it like this: Raspberry Pi 2 Model B > Raspberry Pi 2B

When listing several products and/or models, it's usually possible, and more elegant, to do so without writing out the name of each product or model in full. For example:

Not

Raspberry Pi Zero 2 W, Raspberry Pi 2, Raspberry Pi 3, Raspberry Pi 3+, and Raspberry Pi Compute Module 3

but

Raspberry Pi Zero 2 W, Raspberry Pi 2, 3 and 3+, and Raspberry Pi Compute Module 3

or even, daringly,

Raspberry Pi 2, 3, 3+ and Zero 2 W, and Raspberry Pi Compute Module 3

(note that both examples above omit an Oxford comma where we would usually include one, in the cause of helping the reader to parse the lists correctly).

Other Raspberry Pi products

Almost all accessories, PSUs, and add-on boards take a definite article ("the") before their product name: "the Raspberry Pi Sense HAT", "the Raspberry Pi Mouse", "the Raspberry Pi Touch Display", "the Raspberry Pi High Quality Camera" (note that camera modules do not take a definite article, but the High Quality Camera does; that's to do with how horribly clunky "the Raspberry Pi Camera Module n" sounds). It is usually desirable to omit "Raspberry Pi" from the name in most instances following the first mention. "You can do all kind of experiments with the Raspberry Pi Sense HAT, which is why there are two of them on the International Space Station. The Sense HAT has an array of sensors, a five-button joystick, and an 8x8 RGB LED matrix." "We recommend using the Raspberry Pi USB-C Power Supply, which represents excellent value."

Capitalisation

First word in chapter headings and titles take an initial capital, others lower case. (Sentence case.)

In all text, try to avoid the use of a trademark whose initial letter is in lower case (iPad, element14) at the start of a sentence or title. iPad sales soar is only ever acceptable if typography means that there is insufficient space for Sales of iPad soar.

Abbreviations and acronyms

Spell out abbreviations in the first instance in a chapter section, followed by the abbreviation in parentheses. Thereafter use the abbreviation. Raspberry Pi's brain is a system on a chip (SoC), made by stacking a memory chip on top of a processor chip. Using an SoC keeps the area of the Raspberry Pi board low.

Abbreviations should not be marked in this format: System on a Chip.

See the word list below for correct abbreviations and their capitalisations when spelt out. Be aware that the fact that something is often acronymised does not imply that the thing itself takes capitals. So ASAP does not imply that As Soon As Possible is the correct capitalisation. (Although some acronyms when expanded do require capitalisation: NASA, ASCII etc. Check the word list or Google the organisation if you're not sure.)

Numerals and numbers

Unless you are dealing with code, units of computer storage, or maths materials/equations, spell out numbers one to twelve; express 13 and higher numbers as a numeral unless at the start of a sentence. Eighteen bagpipers were shown to the door.

For a range of numbers, try to keep a consistent format: coding clubs for children aged 9-13, most of the children at the Jam were aged 11-16, one to twenty. Use common sense: if following the style guide looks awful, (coding clubs for children aged nine to 13, one to 20), use a consistent format instead.

For numbers of more than four digits, use commas: 10,000, 100,000. For technical documentation, especially for international audiences (in some languages, a comma is used as a decimal separator), commas may cause confusion, and it's usually better to use thin spaces instead.

Use a space between a value and its SI unit: 2 m, 2 kg, 2 ohm, 8 GB, 5 KiB/s, 1 MiB.

Subscript numerals (e.g. in chemical formulae) are fine in print, but not for online content. So CO2 online, CO₂ in print.

Use the multiplication symbol × when required, not the letter x.

School grades (USA): Spell out first through ninth grade and use figures for 10th grade or higher. Try to keep a consistent format for ranges, as above.

URLs

Omit http://www from URLs in print. Use hyperlinks in online content.

Time and date

Use the 12-hour clock. Include the appropriate time zone abbreviation for North American events. Use a full stop to separate hours and minutes. Separate the time and 'am/pm' with a thin space in print. 5am PDT, 8.20pm, 12 noon EST, 12 midnight, etc.

Dates should be expressed 21 Jan 2006 etc. to avoid confusion with month/day ordering for readers outside the UK. Abbreviate months thus: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec. If it's necessary to include the day of the week as well, Thursday 14 April is acceptable.

Season names should not be capitalised.

An x-week period: hyphen between number and 'week'. A six-week period.

When referring to decades, use the eighties or the 1980s, but never the '80s. When referring to two decades use the 1970s and 1980s, even though the 1970s and '80s more accurately shows how such dates may be read out loud. When the name of a decade is used to define a social or cultural period it should be written as a word.

Race, disability, gender

Indian people (or Egyptian people, black people, Jewish people, etc.) never Indians, Egyptians, blacks or Jews. Similarly, use disabled as an adjective, never a noun. Disabled people, not the disabled.

Example access statement for Picademy: The venue is described as being accessible for people with limited mobility. If you will need to use a car to access the venue, or if you have other access requirements or would like further information, please get in touch via email and let us know how we can help.; further examples: www.accessibilityguides.org/prepare

Copy should be gender neutral as far as possible. Using they as a singular pronoun is acceptable, and is preferable to alternating he and she, which can be clumsy and immersion breaking for the reader. Where possible, make nouns and pronouns plural: Students should enter their passwords is preferable to Each student should enter his or her password.

Avoid gendered job titles; there is usually an alternative. So firefighter instead of fireman; flight attendant instead of stewardess.

Avoid man, mankind, manmade, manpower etc. There are plenty of alternatives.

Screenshots

When screenshotting a window, make sure you are not using dark mode and screenshot the whole desktop, with the mouse cursor not visible unless it is relevant to the screenshot. The design team will crop to fit the relevant templates. If screenshotting multiple windows, there should be no overlapping. (If an author requests overlapping windows for a specific reason, please let the design team know; it can be achieved manually, but should be avoided where possible.)

Screenshots should always be provided as PNG files.

If your screenshot requires annotations, do not add these to the screenshot. Include the instructions separately, and they will be added in the design process.

Text in images

If presenting a screenshot of the Terminal, or any other interfaces which don't provide scalable fonts, use a white background and black text for readability. Dark mode doesn't work well in printed media.

Spelling

In copy written primarily for a UK or an international audience, UK English should be used, with the exception of international organisations- for example, The John F Kennedy Space Center.

In copy intended specifically for a US audience, US English should be used.

Word list

####

• 3D
• 3G, 4G, 5G (phone networks)
• 4K - screen resolution. Upper-case K, close up if modifier added: 4Kp60.
• 50-50 – not fifty-fifty
• 7-inch screen
• 8-bit microprocessor
• 8×, 16× (CD or DVD drive speeds) – note multiplication symbol, not letter x.

###A

• A level — not A Level. She teaches computer science to her A-level students. See for example this DfE documentation.
• A-level computer science — no capitals, even when referring to the curriculum subject. She teaches A-level computer science at Hogwarts.
• AA batteries
• abandonware – old software, where the IP holders are unknown
• Acorn Archimedes (computer) – shorten to Archimedes after first use
• Acorn Computers (company name, produced the BBC Micro and the Acorn family of computers)
• Acorn Electron (computer)
• adapter
• add-on; use 'add-on board', not 'card'
• Advanced Error Reporting - cap up this PCIe term
• adware
• aka – not 'a.k.a.' or 'AKA'
• Allen key – proper noun, capitalise. (Cf. Phillips screwdrivers; why are all the things you screw into other things named after men? Don't answer that.)
• all-expenses-paid trip
• all-ones: used in the adjectival sense, filling something with bits set to 1; "write an all-ones value to the FOO_BAR register"
• all-zeroes: used in the adjectival sense, filling something with bits cleared to 0; "write an all-zeroes value to the FOO_BAZ register"
• ALSA
• AlsaMixer
• AMD (company name)
• amp — ampere. No capital despite derivation from proper noun. 1.2amp or 1.2A (close up, spelling out "amp" is preferred).
• Amstrad (company name)
• Amstrad CPC (computer), short for Amstrad Colour Personal Computer
• analogue
• antenna (pl. antennae)
• antivirus
• app – short form of application. Don’t use if there's potential for confusion
• Apple – Apple trademark. Do not add an s to make plural
• applications processor
• apt — Advanced Package Tool, used in Debian Linux to obtain software (APT is not really an acronym. It was originally, it's just 'apt' now.)
• Arch Linux
• Arm architecture
• Arm chipset
• Arm Holdings (company name) — rebranded from ARM
• Armv6, Armv7
• AS level — see 'A level'
• assembly language
• Astro Pi — find the style guide specific to this programme here
• Atheros (chipset, company name)
• audio conference
• Auto-Tune — capitalise, it's an Antares Audio Technologies trademark. Do not use as a verb.)
• avatar (lower case unless you're talking about the movie!)
• AWG — capitalise. Stands for American Wire Gauge, a US standard set of electrical conductor diameters, used for example in cable specifications

###B

• b - bit = the most basic unit of information in computing and digital communication. The name is a portmanteau of binary and digit! Always use a space between the number and the unit, preferably non-breaking. Use "b" as a suffix only, otherwise explicitly write out "bit". When used as a compound adjective, (e.g. 'The Mega Drive is a 16-bit home video game console'), hyphenate. When used as a quantifier, (e.g. 'These 3 bits control the foo'), do not hyphenate.
• b/s - bits per second. Always use a space between the number and the unit, preferably non-breaking.
• B - byte = 2³ b = 8 b
• B/s - bytes per second. Always use a space between the number and the unit, preferably non-breaking.
• byte - 8 b. The name is both a portmanteau of binary and term as well as a deliberate respelling of bite to avoid accidental mutation to bit. Always use a space between the number and the unit, preferably non-breaking. Use "B" as a suffix only, otherwise explicitly write out "byte". When used as a compound adjective, (e.g. 'The key is stored in a 2-byte register'), hyphenate. When used as a quantifier (e.g. 'These 3 bytes control the foobarbaz'), do not hyphenate.
• B.C. – place after the year. The hoard dates back to around 700 B.C.
• back end (noun), back-end (adjective)
• back-to-school (adjective), back to school (noun)
• backdoor – one word when it's a computer-hacking term
• backlight
• backlit
• backup (noun, adjective), back up (verb)
• bar code
• Bash (Bourne-again shell)
• BBC BASIC – not BASIC (to avoid confusion with Sinclair BASIC and other BASICs)
• BBC Micro
• BBC Model A
• BBC Model B
• Bcc – blind carbon copy. Do not spell out this acronym. (See also Cc.) Also: Bcc'd, Bcc'ing.
• BCM2XXX (eg BCM2835, BCM2837, BCM2711) – SoCs made by Broadcom, used in Raspberry Pi computers. Can be shortened to 2835, 2837, 2711 after first use.
• Beagle Board
• beta — do not capitalise unless part of an official product lane. Raspberry Pi's beta release for developers; try Yahoo! Messenger Beta.
• BGA — ball grid array
• biannual, bimonthly, biweekly – do not use. Instead use every two months or twice a month etc. which is longer, but which avoids confusion.
• big-endian - always use a hyphen, as Jonathan Swift intended
• billion — use numerals with billion: 5 billion people. Abbreviate to bil only if space is at a premium.
• binary
• binary blob — a pejorative term in the free software community. Do not use to refer to the GPU in Raspberry Pi computers.
• binary 1/binary 0 – write the digit, not the number
• BIOS – Basic Input/Output System
• bitstream
• BlackBerry – a Research In Motion (RIM) trademark, so note capitalisation, plural: BlackBerry. BlackBerrys is not correct and can be used only as part of a direct quotation.
• blog
• Blogger – Google trademark when referring to the blogging platform
• blogroll
• Blu-ray – a Blu-ray Disc Association (BDA) trademark, so note capitalisation and hyphen. Use as an adjective only.
• Blu Tack (noun) — Bostik product
• Blu-Tack (verb) — 'to Blu-Tack'/'Blu-Tacked'
• Bluetooth – Bluetooth SIG trademark. Note capitalisation and only use as an adjective.
• Bluetooth Classic
• BluetoothLE
• BMP – bitmap
• bookazine – publishing industry jargon, do not use this in public-facing copy. Use book.
• boot ROM — a small piece of memory containing the first code executed by the processor on startup
• breadcrumb (when referring to website navigation)
• Broadcom
• Brownout — spelled solid; no hyphen, no space
• brute-force — adjective, as in brute-force attack
• BSD — Berkeley Software Distribution

###C

• C (language)
• C# (language)
• C++ (language)
• Camera Module / Camera Module v2 - the official Raspberry Pi camera add-on
• camera phone
• CAN bus
• CAPTCHA – Completely Automated Public Turing Test to Tell Computers and Humans Apart. A rare instance where the first use of an acronym does not need spelling out!
• capture card — HDMI capture card
• CAS – Computing at School
• Cc – carbon copy. Do not spell out this acronym. (See also Bcc.) Also Cc'd, Cc'ing.
• CD – compact disc. Do not spell out this acronym. Plural CDs.
• CD-R — CD-recordable. Plural CD-Rs.
• CD-ROM — CD-read-only memory. Do not spell out this acronym. Plural CD-ROMs.
• CD-RW — CD-rewritable. Plural CD-RWs.
• Celsius — can always be abbreviated to °C
• centimetre (not centimeter)
• Certified Educator (Picademy graduate)
• CGI – computer-generated imaging or common gateway interface or computer graphics interface. Be clear in the first reference in a section which you are referring to before reverting to the acronym.
• champion — lower case, including in the context of CoderDojo ("Thank you to all our wonderful CoderDojo champions and mentors!")
• chat room
• checkbox
• children's
• click — usage depends on the object: use click for a button, link or other interface object, and click on for pictures, icons etc.
• clickable
• client/server – an adjective to describe a kind of network
• clip art
• cloud computing (noun and adjective)
• cm — centimetre. Use a space between the number and cm. My thumb measures 4 cm.
• code, coding - outdated edu-jargon. The praxis is called computer programming or software engineering by people who actually do it for a living. Use these terms instead.
• codebase
• codec – coder/decoder
• CoderDojo — can refer to the network of coding clubs that we run, or to a particular club that is part of the CoderDojo network
• command line
• Commodore 64 (computer)
• Commodore Amiga – shorten to Amiga after first use
• Commodore International — company producing the Commodore family of computers
• Compute Module, Compute Module 3, Compute Module 3 Lite - CM1, CM3, CM3 Lite. Abbreviations should only be used after first using the full product name, and only where repeating the full name would become cumbersome.
• computer science (not computing science) — always lower-case, even when referring to the school subject
• computing — always lower-case, even when referring to the school subject
• cookie – lower case for both biscuits and tracking cookies
• corrupted – use corrupted, not corrupt when describing data. The file is corrupted.
• COVID, or if necessary COVID-19, in capitals (in agreement with the AP style guide)
• crawl – fine as a transitive verb meaning "to sift through" when applied to search engines
• Creative Commons
• cron — time-based job scheduler in Unix-like computer operating systems
• crontab — cron table, a configuration file driving cron that specifies shell commands to run periodically on a given schedule
• CSS – Cascading Style Sheets. Note capitalisation. Lower case style sheets can be used to refer to CSS documents: Cascading Style Sheets (CSS) specifications enable a web designer to use style sheets to lay out a web page.
• CSV – comma-separated values
• CubeSat — not cubesat or cube sat
• curriculum (pl. curricula)
• cut-out — there is a cut-out in the side of the case to make room for the camera cable. Note hyphen, do not close up.
• cyber- – avoid as a prefix where possible: dated. If you do need to use it, don't hyphenate. Cyberattack, cyberterrorism.

###D

• data – treat as a singular noun. The data is lost.
• database
• D-Bus — message bus system. Note capitalisation.
• Debian
• delta-sigma PWM
• Device Tree — a means of representing devices on Raspberry Pi.
• digital age, digital native, digital divide – avoid where possible. Dated jargon.
• Digital Making Curriculum. Also: the Raspberry Pi Foundation's Digital Making Curriculum.
• dialogue – UK spelling
• dingbat – typographical ornament, such as ★.
• dioptre - UK spelling
• disc/disk – magnetic storage is on disks, but optical storage is on discs: floppy disks, compact discs.
• Disney+ — streaming service. Confusingly, "Disney Plus" seems to be used pretty much interchangeably, but "Disney+" appears to be Disney's preference.
• disk space — not disk-space or diskspace
• Document Object Model (DOM) — note capitals
• Dojo — upper case when used to refer to a particular club in the CoderDojo network
• dongle
• DoS – denial-of-service attack
• DOS – Disk Operating System. Acronym for several closely related operating systems.
• dos and don'ts – note apostrophes
• double-click – note hyphen
• drag-and-drop (adjective), drag and drop (verb)
• dreamt
• drop-down menu not pull-down menu
• DV - digital video. Cap up.
• DVD — digital video disc. No need to spell out the acronym in first use.
• DVR — digital video recorder

###E

• e- – generally, hyphenate when a prefix. So: e-book, e-card, e-reader. Note exception for email.
• e-book
• e-commerce
• E-Mark — protocol controller for USB cables. Abbreviation of Electronically Marked. Term of art, so please observe capitalsation. E-Marked is acceptable. Ensure that you are using an E-Marked cable.
• e-paper
• e.g.
• Earth — capitalise when referring to planet, lower case when referring to soil.
• eBay — an eBay trademark
• Ed and Izzy — the two special Astro Pi units sent to the ISS with Tim Peake.
• EEG — electroencephalography
• element14/Premier Farnell in the first instance in a chapter section, then just element14. Element14 should be capitalised if it appears at the beginning of a sentence; in general, try to avoid using at the start of a sentence.
• email
• emoji — pl. emojis (even though this word is Japanese; see tsunami, tsunamis)
• Emotiv — company producing EEG headsets for neuro-signal work.
• end-of-year — adjective before a noun, as in 'end-of-year report'
• endianness - byte order within digital word data
• Endpoint Controller
• EPROM – erasable programmable read only memory
• ePub – electronic publication. An open-standard file format for e-books.
• ESP – email service provider
• -esque – Do not hyphenate words with this suffix unless the suffix creates a double vowel. Turneresque, Dali-esque.
• etc.
• Ethernet (always capitalise)
• EULA – end user licence agreement
• ex. – do not use this abbreviation. Use e.g. instead.

###F

• fan page
• fan site
• fanbase
• FAQ – frequently asked questions. Plural FAQs.
• Fahrenheit – can always be abbreviated to °F
• fax
• fediverse — no cap. A group of federated servers which, although independently administered, can communicate with each other. Mastodon is trying to make the fediverse A Thing, but our experience so far is that users find it very, very hard to get their heads around.
• feed reader
• fetch-decode-execute cycle
• FFmpeg
• file name
• file system
• firewall
• FireWire – trademark
• Flash – do not capitalise Flash when referring to flash memory. If for some reason (why?) you need to refer to the now-deprecated Adobe Flash, use Flash as an adjective, since it is a trademark.
• flash memory — no capital unless at the start of a sentence, Dr Allan.
• Flat Flexible Cable — cap up. FFC is acceptable.
• flatsat — prototype, ground-based test hardware for cubesats. Not flat sat or FlatSat.
• floating-point — adjective, as in 'floating-point number'
• focused — not focussed
• forgo — not forego
• FourCC - four-character code. Note capitalisation.
• frame rate — two words. Had a fight with Sam and Brian about this: two words won.
• friend — can be used as a verb if referring to social networking, but this is grim and unlovely. See unfriend.
• FTP — File Transfer Protocol (note capitalisation)
• full-screen
• function keys

###G

• g – gram(s). Use a numeral with g and no space between the numeral and g. The teabag weighs 7g.
• gamer
• games console. Not "game console", which is the US usage: British usage is "games". See also maths/math.
• Gib - gibibit = 2³⁰ b = 1073741824 b. Always use a space between the number and the unit, preferably non-breaking.
• Gib/s - gibibits per second. Always use a space between the number and the unit, preferably non-breaking.
• Gb - gigabit = 10⁹ b = 1000000000 b. Always use a space between the number and the unit, preferably non-breaking.
• Gb/s - gigabits per second. Always use a space between the number and the unit, preferably non-breaking.
• GiB - gibibyte = 2³⁰ B = 1073741824 B. Always use a space between the number and the unit, preferably non-breaking. Preferred for copy aimed at a technical audience, like datasheets and reference documentation. For content aimed at a general audience, like blog posts, use GB instead to avoid looking like a pedantic nerd.
• GiB/s - gibibytes per second. Always use a space between the number and the unit, preferably non-breaking.
• GB - gigabyte = 10⁹ B = 1000000000 B. Always use a space between the number and the unit, preferably non-breaking. Preferred for content aimed at a general audience, like blog posts. For copy aimed at a technical audience, like datasheets and reference documentation, use GiB (when correct) instead for pedantic nerd cred.
• GB/s - gigabytes per second. Always use a space between the number and the unit, preferably non-breaking.
• Generation X – not Generation Xer
• Generation Y – this used to be the term of art. Since this style guide was conceived the term millennials has been coined and is now dominant in the culture. Feel free to use it.
• Generation Z – zoomers seems to be gaining currency. This one's in a state of flux; let's keep an eye on it.
• geolocation
• geotagging (noun – OK, gerund), geotag (verb)
• GHz – gigahertz. No space between the number and GHz.
• GIF – Graphic Interchange Format. Acronym is always OK. Plural GIFs.
• GitHub
• GNU – the GNU Project. A recursive acronym: GNU is not UNIX.
• GNU Linux
• Google – Alphabet trademark. Google's guidelines say you may not use the trademark as a verb, but common usage says we can ignore them wholesale on this. It's in the OED. That's good enough for me.
• GPIO – general-purpose input/output. Outside materials which are explicitly educative, there shouldn't ever be a need to expand this.
• GPIO Zero – GPIO Zero is the name of the project, but gpiozero is an acceptable alternative when referring to the module
• GPU – graphics processing unit
• grade – for school grades (USA), spell out first through ninth grade and use figures for 10th grade or higher. Try to keep a consistent format for ranges (see Numerals and numbers above).
• gram – see g
• grey – not gray (unless writing for a US audience)
• grown-up – the noun takes a hyphen; it isn't grownup
• GSM – Global System for Mobile Communications
• GStreamer
• GT/s - the PCIe spec says that rates are measured in gigatransfers per second, though MB/s seems to be the unit that many users prefer.
• guestbook
• GUI – graphical user interface
• guizero

###H

• HackSpace magazine – Note capitals. It is no longer the case that we must always include magazine when referring to it.
• Hall effect sensor – capital H
• Hands-on – "a hands-on demo", "get hands-on with Raspberry Pi Pico"
• hardcore
• hashtag – Twitter term
• HAT – Hardware Attached on Top, describing various add-on boards such as the Sense HAT
• HAT+ – new HAT specificiation, beginning Dec 2023. See also Power HAT+.
• HD audio – note capitalisation. Full HD audio is 192kHz; HD audio is 96kHz.
• HMDI – the HDMI authority have emailed to say that the ® symbol is required in the first mention of HDMI in any given document. So HDMI® in the first instance, thereafter HDMI.
• HDTV – high-definition television
• heatsink – not heat sink
• help desk
• help pages
• hi-fi
• hit – do not use as a substitute for press or click
• home page
• host name
• hot swap (noun), hot-swap (verb), hot-swappable, hot swapping
• hotspot – one word when referring to a Wi-Fi access point. Use hot spot if you're talking about a popular restaurant.
• hover – do not use to describe holding a mouse pointer over something on the page. Use hold, pass, or move [your mouse cursor over].
• HTML – Hypertext Markup Language
• Hynix (company name)

###I

• I2C - Inter-Integrated Circuit, used for peripherals on Raspberry Pi; use I2C (no superscript) unless there's a particular reason for using I²C (changed Nov 2020 and consistent across RPTL and Raspberry Pi Press)
• IBM – company name
• IC – integrated circuit
• ICT – information and communications technology, not information and communication technology
• ID – identification. Plural IDs. Avoid using as a verb unless space is very restricted; use apostrophe in verb form. Where possible, The bouncer checks drinkers' identification, not The bouncer ID’s drinkers.
• IDLE - Python IDE installed on Raspbian, found under the Programming menu as 'Python 3 (IDLE)'
• i.e.
• I-frame - Intra frame. Video term. Do not confuse with iframe (inline frame tag in HTML).
• IM – instant message. Plural IMs. Defunct. Use DM or PM instead according to context.
• IMAX – trademark, so use as an adjective, not a noun
• inbox
• inch, in
• index – plural: indices, not indexes (esp. in technical contexts)
• infrared
• inkjet
• install – install on a computer, install to a hard drive
• internet (do not capitalise unless at start of sentence or set in title case, Dr Allan; it is no longer 1997)
• Internet of Things (IoT)
• I/O - not IO. (Old MacDonald had a farm.) BUT see PIO.
• IP – Internet Protocol or intellectual property (note capitalisations)
• iPad – Apple trademark, so do not add an s to make plural
• iPhone – Apple trademark, so do not add an s to make plural
• iPod – Apple trademark, so do not add an s to make plural
• IR – infrared
• ISP – internet service provider
• ISP - image signal processor. Not image sensor pipeline (deprecated).
• IT – information technology

###J

• Java – a Sun Microsystems trademark
• JavaScript – a Sun Microsystems trademark
• JPEG – Joint Photographic Experts Group
• junk mail

###K

• k – do not use as an abbreviation for thousand. When talking about kilobytes, use kB, not k, which is outdated. The original BBC Micro had 32 KiB memory.
• Kib - kibibit = 2¹⁰ b = 1024 b. Always use a space between the number and the unit, preferably non-breaking. Always use an uppercase K.
• Kib/s - kibibits per second. Always use a space between the number and the unit, preferably non-breaking. Always use a uppercase K.
• kb - kilobit = 10³ b = 1000 b. Always use a space between the number and the unit, preferably non-breaking.
• kb/s – kilobits per second. Always use a space between the number and the unit, preferably non-breaking.
• kB – kilobyte. 1000 B. Rarely used; you probably want KiB. Always use a space between the number and the unit, preferably non-breaking. Always use a lowercase k.
• kB/s – kilobytes per second. Always use a space between the number and the unit, preferably non-breaking. Always use a lowercase k.
• KB - Ambiguous, do not use. Use kB or KiB instead.
• KB/s - Ambiguous, do not use. Use kB/s or KiB/s instead.
• KiB - kibibyte = 2¹⁰ B = 1024 B. Always use a space between the number and the unit, preferably non-breaking.
• KiB/s = kibibytes per second. Always use a space between the number and the unit, preferably non-breaking.
• keylogger
• key press
• Key Stage – in UK school system, note upper-case letters
• keyword – search engine term. Think about the best keywords to use on your web page. Use key word when referring to a critical word. She couldn't remember what else he'd said. The key word in his last sentence was "bagpipes".
• kids'
• kg – kilogram(s). No space between number and kg.
• kHz – kilohertz. No space between the number and kHz.
• kilogram
• kilometre
• km – kilometre. No space between the number and unit. We drove 50km.
• kmph – kilometres per hour. No space between the number and kmph.

###L

• l – litre. No space between the number and l. The barman served drinks in 1l glasses.
• LA – Los Angeles. Use only when space is at a premium.
• ladies'
• LAN – local area network
• LCD – liquid-crystal display. Plural LCDs.
• learnt
• LED – light-emitting diode. Plural LEDs.
• left-hand – adjective. Use 'top left-hand side', not 'top left side' or 'top-left side'
• legacy – legacy stack, legacy API etc. do not take an initial capital. The word 'legacy' is not a title.
• Lego – the Lego Group has trademarked LEGO (all caps), but Lego is an acceptable usage. See also splot. Adjective only. Plural Lego bricks, not Legos, which is an abomination unto Nuggan.
• LGBT – lesbian, gay, bisexual, transgender
• libcamera – software library. Lower-case l, do not use at the start of a sentence. (The passive voice has been used a lot today.)
• Li-ion – lithium-ion (a kind of battery)
• licence/license – licence (noun), license (verb). We are not American!
• lightyear
• like – when using as a Facebook verb, enclose in quotation marks. Thousands of people 'like' Raspberry Pi on Facebook, helping the charity to raise funds. If producing online materials and treating the term as a user-interface object (viz. as a link or a button), use a hyperlink to make it stand out, and do not use quotation marks.
• Linux – trademark owned by Linus Torvalds. Not capitalised in the same way as UNIX.
• LiPo – lithium polymer (a kind of battery)
• lithium-ion – do not capitalise when written out in full (cf. Li-ion)
• little-endian - always use a hyphen, as Jonathan Swift intended
• livestream – one word when a noun. Two words when used as a verb
• logic 1/logic 0 – write the digit, not the number
• login – one word when a noun or adjective. Two words when used as a verb. However, try to avoid using as a verb; sign in is preferable because it sounds less technical.
• lookup – one word when a noun or adjective: lookup table or reverse phone number lookup. Two words when a verb. I tried to look up the length of my ex's prison sentence.
• Low speed serial interface (LoSSI)
• LXDE – Lightweight X11 Desktop Environment

###M

• M key - edge connector standard for M.2 PCIe peripherals
• m – metre. No space between the number and m. The sausage measured an amazing 6m.
• M.2
• Mac (for Macintosh) is acceptable usage
• MAC address
• MacBook, MacBook Air, MacBook Pro – Apple trademarks, so do not add an s to make plural
• macOS (not Mac OS, Mac OS X, OS X, or OSX)
• machine – do not use as a synonym for computer. Use computer.
• The MagPi – the official Raspberry Pi magazine
• mailbox
• maker movement – not Maker Movement. Just stop that.
• maker space – things have moved on in the last ten years. This used to be our preferred formulation, but makespace, maker lab, hackspace or maker shed all have currency too now (and at least one of those things has a magazine). Hackspace is probably preferred for branding reasons despite Toby's Maker Lab; refer to the individual organisation's naming preference where possible if writing about specifics.
• malware
• mashup (noun, adjective), mash up (verb)
• mass storage device – not capped up
• Master Boot Record
• Mastodon – social network. Please don't use their Toot coinage: use post instead.
• Maths, not math. Mathematics is also acceptable.
• Mb - megabit = 1000000 b. Always use a space between the number and the unit, preferably non-breaking.
• Mb/s = megabits per second. Always use a space between the number and the unit, preferably non-breaking.
• Mib - mebibit = 2²⁰ b = 1048576 b. Always use a space between the number and the unit, preferably non-breaking.
• Mib/s - mebibits per second. Rarely used; you probably want Mb/s. Always use a space between the number and the unit, preferably non-breaking.
• MB - megabyte = 10⁶ B = 1000000 B. Always use a space between the number and the unit, preferably non-breaking. My old Amiga only had 130 MB drive space.
• MB/s - megabytes per second. Always use a space between the number and the unit, preferably non-breaking.
• MiB - mebibyte = 2²⁰ B = 1048576 B. Always use a space between the number and the unit, preferably non-breaking.
• MiB/s - mebibytes per second. Rarely used; you probably want MB/s. Always use a space between the number and the unit, preferably non-breaking.
• media – treat as a mass noun with a singular verb. The media is paying a lot of attention to Raspberry Pi. However, if you can distinguish a number of individual mediums making up the use of media, use a plural verb. Various media are treating the story differently: print newspapers are not paying much attention, but the TV news and online news sites are very interested.
• meet-up (noun, adjective), meet up (verb). Not meetup.
• mens'
• mentee – never, ever use this horrible neologism. Student or protégé are acceptable substitutions.
• mentor – lower case, including in the context of CoderDojo. Thank you to all our wonderful CoderDojo champions and mentors!
• membership – one has, applies for, pays for, gives, etc. membership of a club, society, association etc.
• message boards
• metadata
• metatag
• mg – miligram(s). No space between the number and mg.
• MHz – megahertz. No space between the number and MHz.
• micro HDMI – lower case if mid-sentence
• micro USB
• micro:bit – a handheld, fully programmable computer which was given free to every Year 7 child across the UK. The Micro:bit Educational Foundation is trying to drop the 'BBC' in front of 'micro:bit'. If using just 'micro:bit', try not to begin sentences with it, due to the lowercase nature of the name.
• Micro:bit Educational Foundation – see here. Note uppercase 'M'.
• microarchitecture, microarchitectural (as opposed to architectural)
• microblog – deprecated. This is what we used to call platforms like Twitter and Tumblr.
• microcontroller
• microprocessor
• MicroPython
• microSD – SanDisk trademark. Don't use at the start of a sentence, because that lower-case 'M' is a nuisance.
• microsite
• Microsoft .Net – Microsoft's trademark guidelines say that Microsoft should precede the .Net brand name in the first instance of use. Because the full stop can create confusion, insert Microsoft before .Net if it occurs at the start of a sentence. Better still, never use the term at all.
• Microsoft Windows – see Windows
• mike – short form of microphone (mic also acceptable)
• million – use numerals and a space with million. Don't hyphenate the numeral and million, even before a noun. If you're forming a compound adjective, use a hyphen between the numeral and million. So: 40 million Raspberry Pis, a £4 million budget, a 4-million-year schedule.
• min. – abbreviation for minute; use only where space is at a premium, and note full stop.
• miniSD – lower-case unless at the start of a sentence/bullet point
• mini HDMI
• mini USB
• mips – million instructions per second. No space between number and mips.
• ml – millilitre(s). No space between the number and ml.
• mm – millimetre(s). No space between the number and mm.
• mobile – acceptable as a noun when it's a short form of mobile phone, but try not to make a habit of it. Cell is becoming more acceptable in the UK, and can be used if preferred.
• money-can't-buy prizes
• moon – lower case, whether referring to the moon or other moons. Mercury does not have a moon.
• mouse – plural mice even when talking about computer peripherals
• mouseover, mouse over – do not use. Use roll or move your mouse cursor over, or an equivalent.
• MP – megapixel. Close up, so a 12MP image.
• MP3 – abbreviation for MPEG-1 Audio Layer 3.
• MPEG – Moving Picture Experts Group. Also refers to a compression methodology whose standards are set by this group.
• MPEG-2, MPEG-2 transport stream
• mpg – miles per gallon. No space between the number and mpg.
• mph – miles per hour. No space between the number and mph.
• MS-DOS – Microsoft Disk Operating System. Trademark for a Microsoft operating system from the DOS family. See DOS.
• multi- – do not hyphenate words with this prefix unless the root word starts with an i or a capital letter. Multiplayer, multicolour, multi-industry.
• multimeter – note spelling. Not multimetre.
• Mylar

###N

• nano – linux text editor. Note lower case. Full name: 'GNU nano'
• NeoPixels – Adafruit trademark
• net – do not capitalise if referring to the internet. Use internet for preference, unless space is tight
• newline – the control character
• news feed
• newsreader – both job title and RSS feed
• Ni-MH – a kind of battery. Note capitalisation differs on expansion; cf. nickel-metal hydride.
• NIC – network interface card
• nickel-metal hydride – see Ni-MH
• Ninja – upper case when used in the context of CoderDojo, but frankly I'd be happy never to have to use it again
• no-no
• No. 1 – see number one
• no one - do not hyphenate
• Node-RED – a visual tool for wiring the Internet of Things
• Node.js
• NOOBS – New Out Of Box Software, used to easily install an operating system on Raspberry Pi. Deprecated.
• number one – no hyphen as adjective. Bagpipes are my number one hate. Abbreviate as No. 1 if space is tight.
• NVMe
• NYC – New York City. Use only if space is tight.

###O

• object-oriented programming
• OEM – original equipment manufacturer. Preferable to factory when talking about the place where Raspberry Pi computers are made.
• offline
• offshoot
• off-screen
• ohm – not capped (although it derives from a proper name). When talking about resistors, 1Ω, not 1R.
• OK – not okay, Ok or ok. OK?
• on-board (adjective), on board (adverb), when referring to PCBs. "There is an on-board wireless antenna", but "There is a wireless antenna on board".
• onboard (adjective), on board (adverb), when referring to vessels and vehicles. "There are two Raspberry Pi computers on board the International Space Station." "Input from sensors in the hull is sent to the ship's onboard computer."
• online
• on-screen (adjective), on screen (adverb)
• OpenOCD
• open source – no hyphen whether used as a noun or as an adjective. We would usually hyphenate a term such as this when used as an adjective, according to the advice of New Hart's Rules; however, no one else does this, so we would look fussy and stuffy if we did.
• opt-in (noun, adjective), opt in (verb)
• organiser (s, not z)
• OS – operating system. Plural OSes.
• outbox
• overclocking (noun), overclock (verb). Never the verb clock, which may mean something else entirely. If in doubt, clarify. For example, dynamic frequency clocking.
• overcurrent – spelled solid; no hyphen, no space
• overvoltage – spelled solid; no hyphen, no space
• overwrite – spelled solid; no hyphen, no space

###P

• P2P – peer-to-peer
• Pac-Man (game)
• page view
• passcode
• passphrase
• password
• password-protect (verb)
• PayPal – an eBay trademark
• PC – personal computer. Make context clear to avoid confusion with politically correct.
• PCB – printed circuit board
• PCIe
• PCIe connector – this is a standard that Raspberry Pi 5 is not using. Write "Raspberry Pi connector for PCIe" instead.
• PCIe 3.0 x1 – letter x, not multiplication symbol
• PDF (Portable Document Format, Adobe file format)
• peer-to-peer (adjective)
• percent
• Peripheral Address Map
• Perl
• pharming – redirecting traffic from a website that looks legitimate to a spoof website
• PhD
• Phillips screwdrivers, Phillips screw - proper noun, takes a cap. Not a trademark, nothing to do with Philips the lightbulb/hair-removal people. Your editor draws this to your attention because ESA once got very confused about it when we mentioned a screwdriver in an ISS video.
• phishing – tricking someone into giving out sensitive information using an email that looks legitimate
• photobooth
• Photoshop – Adobe trademark. Use as an adjective or proper noun, and never as a verb.
• Pi-hole - note capitalisation. Don't know about you, but I find objectionable capitalisation 100% more objectionable when the word "Pi" is involved.
• PIO – programmable I/O. Not PI/O or any other abomination
• PiServer – a piece of software created by us for centrally controlling fleets of Raspberry Pis (e.g. in a classroom)
• Pi In The Sky (PITS) board
• Picademy – training courses for teachers. If possible, pluralise by adding 'sessions', 'courses' or similar.
• picamera, picamera2 – software libraries which provide a pure Python interface to Raspberry Pi cameras. Contain the PiCamera class (among others). Note capitalisation.
• PIN – acronym for personal identification number. PIN number is tautological but acceptable.
• PipeWire
• playlist
• PlayStation – Sony trademark. Do not add an s to make plural.
• podcast
• PoE – power over Ethernet
• polyfuse
• pop-up (noun, adjective), pop up (verb). Not popup.
• pope – lower case unless referring to a specific named pope. The pope wants a Raspberry Pi. The Queen met Pope Benedict XVI.
• Post-it – 3M trademark. Do not use as a noun. Plural Post-it notes.
• Power HAT+
• pre- – close up pre- as a prefix with the root word unless the root word starts with an e or a capital letter, in which case hyphenate. Preprandial, pre-election, pre-MP3. Exception: pre-soldered.
• press – when talking about a key on a keyboard, use press. Click is for buttons, links and other interface elements, and click on is for the mouse action.
• print
• printout (noun), print off (verb)
• pro forma statement, pro forma income statement - not "pro-forma"
• program (computer)
• programme (television, theatre etc.)
• PS2, PS3, PS4, PS5 – acceptable abbreviations for Sony's PlayStation 2, PlayStation 3, PlayStation 4 and PlayStation 5.
• pseudocode
• pull-up - resistor used in electronic logic circuits (https://en.wikipedia.org/wiki/Pull-up_resistor), can be shortened to PU during repeated heavy usage
• pull-down - resistor used in electronic logic circuits (https://en.wikipedia.org/wiki/Pull-down_resistor), can be shortened to PD during repeated heavy usage
• PulseAudio
• Puppy Linux
• PuTTY: popular SSH/Telnet software used to access Raspberry Pi
• Pygame
• Pygame Zero
• Python (language)

###Q

• Q&A
• QR code
• quad-core – hyphenated when modifying a noun (processor, computer, etc.)
• QuickTime – Apple trademark
• Qt
• QtGL

###R

• RAM – random access memory
• Raspberry Pi icon – not Raspberry Icon or raspberry icon.
• Raspberry Pi menu – not Raspberry Pi Menu or Raspberry menu or any of your other nonsense, Jepson. :P
• Raspberry Pi – plural Raspberry Pis. Do not abbreviate, however much you want to.
• Raspberry Pi 1, Raspberry Pi 2, Raspberry Pi 3B+, Raspberry Pi 4 etc.
• Raspberry Pi 3-pin Debug Connector Specification - a standard we have developed (see here). Capitalise the name of the specification and abbrevations thereof: our Debug Connector Specification, the Raspberry Pi 3-pin Debug Specification, etc (just as we do with abbreviations of the names of hardware products). Don't capitalise descriptive references that are not the name of the spec: the Raspberry Pi debug connector standard.
• Raspberry Pi Foundation – requires a definite article: The Raspberry Pi Foundation works with ESA to let kids run code in space.
• Raspberry Pi OS – does not take a definite article: Raspberry Pi OS is our official recommended operating system.
• Raspberry Pi Weekly (a weekly email newsletter)
• Raspberry Pi Zero
• Raspberry Pi Zero W (not 'Wireless')
• Raspbian
• Raspbian Lite
• re- – close up this prefix with root words unless the root word starts with an e or a capital letter. If it does, hyphenate. There are exceptions to this rule for the avoidance of confusion with other words: re-create, re-cover, re-sent.
• real time (noun), real-time (adjective)
• reality TV
• Resource Repository – capitalised when referring to the NCCE Resource Repository. We are building a resource repository called the Resource Repository.
• RetroPie – not Retropie or RetroPiE
• retweet
• right-click
• right-hand - adjective. Use 'top right-hand side', not 'top right side' or 'top-right side'
• ringtone
• rock 'n' roll
• ROM – read-only memory
• Roku – company name and name of streaming media device. Trademark. Do not add s to make plural. Plural Roku boxes or Roku devices.
• roundup
• RP2040 - the full name of this product is simply "RP2040", not "Raspberry Pi RP2040"
• RS Components – in full in the first instance in a chapter section, then just RS.
• RSS – Really Simple Syndication. Best practice is to use RSS feed, RSS news feed or RSS newsreader; few people know what RSS means on its own, and it's much less used in these dark days of the 2020s than it was when this guide was first written.
• RTC – real-time clock

###S

• SanDisk (company)
• Schmitt trigger
• screen – should only refer to a computer or television screen, not a page on a website.
• screen name
• screen reader (accessibility tool)
• screencast
• screengrab
• screensaver
• screenshot
• scroll bar
• scroll wheel
• SDA – SD Card Association, developers of SD, SDHC etc. cards
• SD card – Secure Digital memory card format
• SDHC card – Secure Digital High-Capacity card
• search engine
• Secure Boot is a standard. Things can boot securely without adhering to the standard. Note caps.
• security key
• setup (noun, adjective), set up (verb)
• short code – two words when referring to a mobile phone
• shutdown – noun. Shut down is the verb.
• sidebar
• sign-in (noun, adjective); sign in, sign in to (verb). Preferable to log in or log on; sounds less technical.
• sign-out, sign-up – see sign-in
• SIM card – subscriber identity module card
• Sinclair ZX81 (cf. ZX Spectrum)
• single-board computer
• SiP – system in package
• site map
• slideshow
• smart card
• smartphone
• SMS – short message service
• snail mail – just no. Use the post or similar.
• SoC – system on chip
• social media – treat as media
• social network (noun), social-network (adjective)
• social networking (noun), social-networking (adjective)
• SODIMM (no hyphen)
• software – collective noun; when singular, never write 'a software' (seriously, we've seen news outlets who should know better use this); always write 'a piece of software' (preferred) or 'a software program'
• SoM – system on module
• sound bite
• soundcheck
• soundstage
• southbridge – a bit dated, and very ASIC-engineer specific. 'I/O controller chip' is preferred, unless in technical writing.
• spam
• spammer
• spell-checker, spell-check
• splot – the individual nubble on a Lego brick. A Raspberry Pi fits into a case measuring seven by eleven splots.
• spyware
• SSH
• standalone
• startup (noun, adjective), start up (verb)
• STL – not .stl or .STL
• style sheet – lower case even when referring to CSS (which you probably aren't referring to, but you know. Just in case). See CSS.
• sub- – close up this prefix with the root word unless the root word starts with a capital letter, in which case hyphenate. Subdomain, sub-Victorian.
• substring
• sulphur – not sulfur, despite the Royal Society of Chemistry's best efforts
• supercapacitor – all one word
• SWD – Serial Wire Debug
• sync, synched, synching

###T

• T-shirt
• TeachMeet
• TensorFlow
• terminal, Terminal – when talking about using the command line in the GUI, 'open a terminal window' or 'type [something] into the terminal' (never LXTerminal or similar). The application for using the terminal on Raspberry Pi OS is also called Terminal (proper noun, capital letter). How-to instructions aimed at people who might be unfamiliar with the command line should specify 'open Terminal' before advising people to 'type [whatever] into the terminal'.
• Tetris (game)
• text message (noun), text-message (adjective, verb). Acceptable to shorten to text
• thin client – do not hyphenate, whether used as a noun or as an adjective. We would usually hyphenate a compound term of this kind when used as an adjective, but because no one else does, doing so would look fussy.
• third-best selling general-purpose computer
• third-party, not 3rd party
• thousand – spell out when in inline text
• thumb drive
• TikTok
• Timelapse
• timeshift, timeshifting
• title bar
• TiVo – trademark. Do not use as a verb or add an s to make plural.
• to-do – plural to-dos. Capitalise as To-Do in title case.
• toolbar
• tooltip
• TOS – terms of service
• touchpad
• touchscreen
• towards – not toward
• trackball
• trackpad
• trade show
• transport stream - MPEG-2 transport stream. Note capitalisation.
• traveller, travelled, travelling
• Trinket – the service provided on the trinket.io website, as well as the organisation. Note that capitalisation is used inconsistently in their website copy, so this usage is a judgement call by us. See below.
• trinket/trinkets – projects on trinket.io. See above.
• Trojan horse
• troubleshoot
• TV (no need to spell out what the acronym means!)
• tweet
• Twitter – Capitalise when talking about the website. Do not use as a verb to refer to communicating on Twitter. Use tweet instead.
• Twitter thread

###U

• UART – universal asynchronous receiver/transmitter
• UF2
• UI – user interface
• UK
• UN
• undervoltage - not under voltage
• unfriend – see friend
• Unix - the trademark is UNIX, but common usage seems to dictate Unix
• unsubscribe
• up-to-date
• URL – Uniform Resource Locator, but abbreviation is always OK and doesn't need to be spelt out in the first instance
• USA
• USB – universal serial bus
• USB C, USB 2 etc. Not USB Type-C in blog posts, magazine articles or books like the Beginner's Guide, but Type-C etc. is acceptable in writing geared for a more technical audience.
• USB flash drive
• USB On-The-Go, USB OTG – hyphenate if expanded
• user
• user base
• username
• userID
• userland – OS software that does not belong in the kernel

###V

• VGA – video graphics array
• video camera
• video game
• videoconference
• voicemail
• VoIP – voice over Internet Protocol
• volt – not capitalised. But takes a capital V when abbreviated, so 3.3V (closed-up, and not 3V3). Sorry-not-sorry, Alasdair.
• VPN – virtual private network

###W

• walkthrough – one word
• wallpaper, wallpapers
• WAN – wide area network
• web
• webcam
• womens'
• webcast
• webinar (ghastly, but it appears we're stuck with it – ten points for you, dear writer, if you can avoid using it)
• webisode (see webinar)
• weblog – use only when explaining the etymology of the word blog, which is always to be preferred
• web browser
• webmaster
• web page
• web server
• website
• WhatsApp
• white paper – two words, lower case, as preferred by both AP and Guardian/Observer style guides (2021/07/02)
• widescreen
• Wi-Fi:registered: – if referring to a Raspberry Pi product, do not use this; refer to the built-in WiFi as 'wireless LAN' or similar. Newsflash! The Wi-Fi Alliance has now altered its rules to say that non-members are allowed to use the term. Wi-Fi, not WiFi, and needs to be followed by the ®️ symbol. No need to expand to wireless (Wi-Fi) when first using in a document; Wi-Fi is common-enough usage that we can consider it standard English.
• Wii – Nintendo trademark. Do not add an s to make plural.
• Wiimote – controller for the Wii. Colloquial. (The official term is Wii Remote.)
• wiki – plural wikis
• Windows – trademark: use Microsoft Windows if talking about the Microsoft product to differentiate from other windowing software
• Windows CE – trademark. Not Microsoft Windows CE
• Wine – application to allow Microsoft Windows software to run on UNIX-like operating systems. Originally an acronym for WINdows Emulator, later changed to a recursive “backronym” for Wine Is Not an Emulator.
• word mark – not wordmark
• word processing (noun), word-processing (adjective)
• word-of-mouth
• WordPress – trademark
• workflow
• World Wide Web
• writable
• WWW
• WYSIWIG – what you see is what you get

###X

• X – social network formerly known as Twitter. If we do end up having to reference it, use language like "X, formerly known as Twitter."
• X-ray
• x86 architecture
• Xbox – Microsoft trademark. Do not add "es" to make plural.
• xHCI
• XHTML – Extensible Hypertext Markup Language
• XML – Extensible Markup Language
• X Windows - GUI framework

###Y

• Yahoo! – use the upper case Y and the exclamation mark when referring to the company or its brands
• YouTube – Google trademark

###Z

• ZX Spectrum
• zip file