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 dc90e0690f..3e547e9869 100644
--- a/eo-runtime/src/main/eo/org/eolang/math/e.eo
+++ b/eo-runtime/src/main/eo/org/eolang/math/e.eo
@@ -26,4 +26,6 @@
 +version 0.0.0
 
 # The Euler's number.
+# A fundamental mathematical constant approximately equal to 2.7182818284590452354.
+# When dataized, it represents the base of natural logarithms.
 2.7182818284590452354 > e
diff --git a/eo-runtime/src/main/eo/org/eolang/negative-infinity.eo b/eo-runtime/src/main/eo/org/eolang/negative-infinity.eo
index 0978f26f62..e09b675e95 100644
--- a/eo-runtime/src/main/eo/org/eolang/negative-infinity.eo
+++ b/eo-runtime/src/main/eo/org/eolang/negative-infinity.eo
@@ -26,6 +26,8 @@
 +version 0.0.0
 
 # Negative infinity.
+# A special floating-point value representing an unbounded quantity less than all real numbers.
+# When dataized, it signifies an unbounded lower limit or an unreachable maximum value.
 [] > negative-infinity
   number FF-F0-00-00-00-00-00-00 > @
   $ > floor
@@ -35,13 +37,13 @@
   false > is-integer
   error "Can't convert negative infinity to i64" > as-i64
 
-  # Tests that $ = x.
+  # Tests that the value $ is equal to x.
   [x] > eq
     eq. > @
       ^.as-bytes
       x.as-bytes
 
-  # Tests that $ < x.
+  # Tests that the value $ less than x.
   [x] > lt
     x > value!
     not. > @
@@ -49,19 +51,19 @@
         (number value).is-nan
         ^.eq value
 
-  # Tests that $ <= x.
+  # Tests that the value $ less or equal than x.
   [x] > lte
     x > value!
     not. > @
       (number value).is-nan
 
-  # Tests that $ > x.
+  # Tests that the value $ greater than x.
   false > [x] > gt
 
-  # Tests that $ >= x.
+  # Tests that the value $ greater or equal than x.
   ^.eq x > [x] > gte
 
-  # Multiplication of $ and x.
+  # Returns the result of the multiplication of $ and x.
   [x] > times
     x > value!
     number value > num
@@ -75,7 +77,7 @@
         ^
         positive-infinity
 
-  # Sum of $ and x.
+  # Returns the result of the sum of $ and x.
   [x] > plus
     x > value!
     if. > @
@@ -85,7 +87,7 @@
       nan
       ^
 
-  # Difference between $ and x.
+  # Difference between the values of $ and x.
   [x] > minus
     x > value!
     if. > @
diff --git a/eo-runtime/src/main/eo/org/eolang/positive-infinity.eo b/eo-runtime/src/main/eo/org/eolang/positive-infinity.eo
index 200aaf9a6b..ceec97a5d9 100644
--- a/eo-runtime/src/main/eo/org/eolang/positive-infinity.eo
+++ b/eo-runtime/src/main/eo/org/eolang/positive-infinity.eo
@@ -26,6 +26,8 @@
 +version 0.0.0
 
 # Positive infinity.
+# A special floating-point value representing an unbounded quantity greater than all real numbers.
+# When dataized, it signifies an unbounded upper limit or an unreachable maximum value.
 [] > positive-infinity
   number 7F-F0-00-00-00-00-00-00 > @
   $ > floor
@@ -35,19 +37,19 @@
   false > is-integer
   error "Can't convert positive infinity to i64" > as-i64
 
-  # Tests that $ = x.
+  # Tests that the value $ is equal to x.
   [x] > eq
     eq. > @
       ^.as-bytes
       x.as-bytes
 
-  # Tests that $ < x.
+  # Tests that the value $ less than x.
   false > [x] > lt
 
-  # Tests that $ <= x.
+  # Tests that the value $ less or equal than x.
   ^.eq x > [x] > lte
 
-  # Tests that $ > x.
+  # Tests that the value $ greater than x.
   [x] > gt
     x > value!
     not. > @
@@ -55,13 +57,13 @@
         (number value).is-nan
         ^.eq value
 
-  # Tests that $ >= x.
+  # Tests that the value $ greater or equal than x.
   [x] > gte
     x > value!
     not. > @
       (number value).is-nan
 
-  # Multiplication of $ and x.
+  # Returns the result of the multiplication of $ and x.
   [x] > times
     x > value!
     number value > num
@@ -75,7 +77,7 @@
         ^
         negative-infinity
 
-  # Sum of $ and x.
+  # Returns the result of the sum of $ and x.
   [x] > plus
     x > value!
     if. > @
@@ -85,7 +87,7 @@
       nan
       ^
 
-  # Difference between $ and x.
+  # Difference between the values of $ and x.
   [x] > minus
     x > value!
     if. > @
diff --git a/eo-runtime/src/main/eo/org/eolang/tuple.eo b/eo-runtime/src/main/eo/org/eolang/tuple.eo
index cd6ef710a6..85317f3575 100644
--- a/eo-runtime/src/main/eo/org/eolang/tuple.eo
+++ b/eo-runtime/src/main/eo/org/eolang/tuple.eo
@@ -26,8 +26,10 @@
 +version 0.0.0
 
 # Tuple.
+# An ordered, immutable collection of elements.
 [head tail] > tuple
   # Empty tuple.
+  # A tuple with no elements. When dataized, it represents an immutable, empty collection.
   [] > empty
     0 > length
 
@@ -37,7 +39,7 @@
     # Create a new tuple with this element added to the end of it.
     tuple ^ x > [x] > with
 
-  # Obtain the length of the tuple.
+  # Obtain the length value of the tuple.
   [] > length
     head.length.plus 1 > len!
     number len > @
diff --git a/eo-runtime/src/main/eo/org/eolang/txt/text.eo b/eo-runtime/src/main/eo/org/eolang/txt/text.eo
index cd11c0652a..d1d9607771 100644
--- a/eo-runtime/src/main/eo/org/eolang/txt/text.eo
+++ b/eo-runtime/src/main/eo/org/eolang/txt/text.eo
@@ -241,7 +241,7 @@
           ^.rec-index-of-substr
             idx.plus -1
 
-  # Returns `text` in upper case.
+  # Returns the `text` in upper case.
   [] > up-cased
     ascii "z" > ascii-z!
     ascii "a" > ascii-a!
@@ -277,7 +277,7 @@
             00-00-00-00-00-00-00
             char.as-bytes
 
-  # Returns `text` in lower case.
+  # Returns the `text` in lower case.
   [] > low-cased
     ^.up-cased.ascii "Z" > ascii-z
     ^.up-cased.ascii "A" > ascii-a