diff --git a/eo-runtime/src/main/eo/org/eolang/fs/file.eo b/eo-runtime/src/main/eo/org/eolang/fs/file.eo
index 1270c8fca6..f3394be06d 100644
--- a/eo-runtime/src/main/eo/org/eolang/fs/file.eo
+++ b/eo-runtime/src/main/eo/org/eolang/fs/file.eo
@@ -28,7 +28,7 @@
 +rt node eo2js-runtime:0.0.0
 +version 0.0.0
 
-# A file on the filesystem.
+# The file object in the filesystem.
 [path] > file
   $.path > @
 
@@ -67,13 +67,13 @@
           ^
       ^
 
-    # Deletes the file and and returns `true`.
+    # Deletes the file and returns `true`.
     #
     # Attention! The object is for internal usage only, please
     # don't use the object programmatically outside of `file` object.
     [] > delete /org.eolang.true
 
-  # Get file size in bytes.
+  # Gets the file size and returns it in bytes.
   [] > size /org.eolang.number
 
   # Move current file to `target`, making and returning a new `file` from it.
@@ -89,7 +89,7 @@
     # don't use the object programmatically outside of `file` object.
     [] > move /org.eolang.string
 
-  # Convert the `file` to `path`.
+  # Convert the `file` to the `path`.
   (QQ.fs.path ^.path).determined > [] > as-path
 
   # Opens the file.
diff --git a/eo-runtime/src/main/eo/org/eolang/fs/path.eo b/eo-runtime/src/main/eo/org/eolang/fs/path.eo
index f307fbbf53..70cb828892 100644
--- a/eo-runtime/src/main/eo/org/eolang/fs/path.eo
+++ b/eo-runtime/src/main/eo/org/eolang/fs/path.eo
@@ -422,6 +422,7 @@
       # | root relative      | drive relative | other             |
       # | root relative      | root relative  | other             |
       # |--------------------|----------------|-------------------|
+      # URI Resolution Rules.
       [other] > resolved
         ^.uri > uri-as-bytes!
         ^.separated-correctly other > valid-other!
@@ -523,6 +524,7 @@
       # | "Hello, Jeff"                | "Hello, Jeff"      |
       # | ""                           | ""                 |
       # |------------------------------|--------------------|
+      # Extracting Directory Names from File Paths.
       [] > dirname
         ^.uri > pth!
         text > txt
diff --git a/eo-runtime/src/main/eo/org/eolang/math/e.eo b/eo-runtime/src/main/eo/org/eolang/math/e.eo
index e720a08291..91e24c3919 100644
--- a/eo-runtime/src/main/eo/org/eolang/math/e.eo
+++ b/eo-runtime/src/main/eo/org/eolang/math/e.eo
@@ -25,5 +25,5 @@
 +package org.eolang.math
 +version 0.0.0
 
-# The Euler's number
+# The Euler's number.
 2.7182818284590452354 > e
diff --git a/eo-runtime/src/main/eo/org/eolang/math/real.eo b/eo-runtime/src/main/eo/org/eolang/math/real.eo
index 2d6647ed69..31cf22d9e6 100644
--- a/eo-runtime/src/main/eo/org/eolang/math/real.eo
+++ b/eo-runtime/src/main/eo/org/eolang/math/real.eo
@@ -28,7 +28,7 @@
 +rt node eo2js-runtime:0.0.0
 +version 0.0.0
 
-# Real number.
+# Returns a floating point number.
 [num] > real
   num > @
   # Returns Euler's number raised to the power of a `num`.
diff --git a/eo-runtime/src/main/eo/org/eolang/nan.eo b/eo-runtime/src/main/eo/org/eolang/nan.eo
index c68a590b57..7d3d051e35 100644
--- a/eo-runtime/src/main/eo/org/eolang/nan.eo
+++ b/eo-runtime/src/main/eo/org/eolang/nan.eo
@@ -50,13 +50,13 @@
   # Tests that $ >= x.
   false > [x] > gte
 
-  # Multiplication of $ and x.
+  # Returns the multiplication of $ and x.
   ^ > [x] > times
 
   # Sum of $ and x.
   ^ > [x] > plus
 
-  # Difference between $ and x.
+  # Returns the difference between $ and x.
   ^ > [x] > minus
 
   # Quotient of the division of $ by x.
diff --git a/eo-runtime/src/main/eo/org/eolang/structs/list.eo b/eo-runtime/src/main/eo/org/eolang/structs/list.eo
index d26e7404f1..a3201a18a6 100644
--- a/eo-runtime/src/main/eo/org/eolang/structs/list.eo
+++ b/eo-runtime/src/main/eo/org/eolang/structs/list.eo
@@ -30,7 +30,7 @@
 [origin] > list
   origin > @
 
-  # Is it empty?
+  # Is it empty?.
   0.eq ^.origin.length > [] > is-empty
 
   # Create a new list with this element added to the end of it.