Illustrate
来自Big Physics
early 16th century (in the sense ‘illuminate, shed light on’): from Latin illustrat- ‘lit up’, from the verb illustrare, from in- ‘upon’ + lustrare ‘illuminate’.
wiktionary
Back-formation from illustration. [1]
etymonline
illustrate (v.)
1520s, "light up, shed light on;" 1610s, "educate by means of examples," back-formation from illustration, and in some cases from Latin illustratus, past participle of illustrare "light up, make light, illuminate." Sense of "provide pictures to explain or decorate" is 1630s. Related: Illustrated; illustrating.