Origin: Latin suffix -tion
Illustration has 5 different meanings across 1 category:
artwork that helps make something clear or attractive
"The textbook included colorful illustrations to help students better understand complex scientific concepts."
showing by example
"The teacher used the story as an illustration showing how patience can solve conflicts without words."
an item of information that is typical of a class or group
"this patient provides a typical example of the syndrome"
"there is an example on page 10"
a visual representation (a picture or diagram) that is used make some subject more pleasing or easier to understand
"The textbook page featured an illustration of the cell's structure to help students visualize how it functions."
The act of illustrating; the act of making clear and distinct;
"The teacher's patient illustration made the complex scientific concept easy to understand for every student in the room."
In plain English: An illustration is a picture that helps explain something written in a book or story.
"The book used simple illustrations to explain complex scientific concepts for children."
Usage: Use this noun to refer specifically to an image or diagram that explains text, rather than using it as a synonym for general explanation. It is often confused with "illustrate" when people mistakenly treat the word as a verb in casual speech.
The word entered English via the Old French term illustracion, which was borrowed directly from the Latin verb meaning "to make bright or clear." Originally referring to shining light upon something, it evolved in usage to describe any visual representation that clarifies a text.