/ Dictionary / Index A assumption: Meaning and Definition of Find definitions for: as•sump•tion Pronunciation: (u-sump'shun), [key] — n. something taken for granted; a supposition: a correct assumption. the act of taking for granted or supposing. the act of taking to or upon oneself. the act of taking possession of something: the assumption of power. arrogance; presumption. the taking over of another's debts or obligations. (often cap.) the bodily taking up into heaven of the Virgin Mary. (cap.) a feast commemorating this, celebrated on August 15. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: assumption (Thesaurus) assumpsit Assumptionist Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language