1590s, "one who enlightens," agent noun in Latin form from illustrate, or from Late Latin illustrator "an enlightener." Meaning "one who draws pictures" is 1680s.
Entries linking to illustrator
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.