early 15c., altered from presupponen (c. 1400), "assume beforehand or in the beginning," from Old French presupposer (14c.), formed in French or else from Medieval Latin praesupponere; see pre- + suppose. The meaning "take for granted in advance of actual knowledge or experience" is from 1520s. Related: Presupposed; presupposing.
updated on October 28, 2020