Is a window the same as a split? (and related)

[jerabaul29]

I get a bit confused around the concepts of window vs split. For example, after doing a ctrl-w , I get:

which mentions both windows and splits. Are the 2 concepts the same or not? For me it looks like they are the same (for example, if I open a split, then using close window closes the new split; similarly, next window moves to the next split).

If window = split, maybe it would be useful to default to one single word? (I would vote for only using the word split not the word window, but the opposite would certainly be fine too).

If window != split, any way this can be explained / documented? Wondering if having a short introduction to the concepts of buffers, windows / splits, maybe at some point tab if something along the lines of #7109 gets merged, could be useful for new users? :)