Merriam-Webster Collegiate Dictionary - assumption

 noun  Etymology: Middle English, from Late Latin ~-, assumptio taking up, from Latin assumere  Date: 13th century  1.  a. the taking up of a person into heaven  b. capitalized August 15 observed in commemoration of the Assumption of the Virgin Mary  2. a taking to or upon oneself the ~ of a new position  3. the act of laying claim to or taking possession of something the ~ of power  4. arrogance, pretension  5.  a. an assuming that something is true  b. a fact or statement (as a proposition, axiom, postulate, or notion) taken for granted  6. the taking over of another's debts