"provided with drawings, etc., as illustration," 1831, past-participle adjective from illustrate (v.).
Entries linking to illustrated
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.