iˈllustratory,a. [f. L. illustrāt-(see illustrative) + -ory.] Illustrative. a1734North Exam. (1740) 660 Introductory, illustratory, preparatory abuses of Truth [etc.].1806Scott Fam.Lett. 5 July (1894) I. ii. 36 Dryden's works..with notes critical and illustratory by the Editor.