Meaning of “illustrate” - Learner’s Dictionary

illustrate

verb [ T ] uk us /ˈɪləstreɪt/
GIVE EXAMPLE

to give more information or examples to explain or prove something:

to illustrate a point/problem
[ + question word ] This new discovery illustrates how little we know about early human history.
DRAW PICTURE

B2 to draw pictures for a book, magazine, etc:

an illustrated children's book

(Definition of “illustrate” from the Cambridge Learner’s Dictionary © Cambridge University Press)