Other forms: illustrated, illustrates, illustrating
To illustrate something is to make it clear — with a picture, an example, or a story. A book is illustrated with drawings; a point is illustrated with a case.
Both senses are common and they pull in different directions, so the object tells you which is meant: illustrate a book means pictures, illustrate a point means examples. The second is the one that matters in academic and business writing, and the standard patterns are illustrate how, illustrate why, and as this illustrates. An illustrator draws for a living; an illustration is either the picture or the example. Note that illustrate does not mean explain — it shows rather than tells, and something can be well illustrated and still not understood.
1verbillustrateTo make something clear by giving an example.
“The case illustrates how easily the rule can be misread.”
synonyms: demonstrate, show, exemplify
2verbprovideTo provide a book or article with pictures.
“She illustrated three children's books that year.”
illustrate is a way of making clear.
Back-formation from illustration. a back-formation from illustration.
Etymology from Wiktionary, CC BY-SA