to require or imply as a necessary prior condition
(philosophy, logic, linguistics) to require (a condition) to be satisfied as a precondition for a statement to be either true or false or for a speech act to be felicitous. Have you stopped beating your wife? presupposes that the person addressed has a wife and has beaten her
1530s, from Middle French présupposition and directly from Medieval Latin praesuppositionem (nominative praesuppositio), noun of action from past participle stem of Latin praesupponere, from prae "before" (see pre-) + suppositio (see suppose).
mid-15c., from Old French presupposer (14c.), from Medieval Latin praesupponere; see pre- + suppose. Related: Presupposed; presupposing.