Pronunciation: (prē"su-pōz'), [key]
—v.t., -posed, -pos•ing.
1. to suppose or assume beforehand; take for granted in advance.
2. (of a thing, condition, or state of affairs) to require or imply as an antecedent condition: An effect presupposes a cause.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.