1. The act of taking to or upon oneself: assumption of an obligation.
2. The act of taking possession or asserting a claim: assumption of command.
3. The act of taking for granted: assumption of a false theory.
4. Something taken for granted or accepted as true without proof; a supposition: a valid assumption.
5. Presumption; arrogance.
6. Logic. A minor premise.
7. Assumption
   1. Christianity. The taking up of the Virgin Mary into heaven in body and soul after her death.
   2. A feast celebrating this event.
   3. August 15, the day on which this feast is observed.

[Middle English assumpcion, from Latin assūmptiō, assūmptiōn-, adoption, from assūmptus, past participle of assūmere, to adopt. See assume.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.