The act of assuming; the thing, often the postulate or proposition, assumed; the minor proposition in a categorical syllogism; the taking up a person into heaven; in particular a festival of the Romish and Greek Churches, celebrated in honour of the miraculous ascent of the Virgin Mary to heaven.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (noun) (n.) (noun)
The act of taking to or upon oneself; the act of taking for granted; the thing supposed; arrogance; supposition; a disposition to claim more than is one's due.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (noun) (n.) (noun)
The act of assuming; supposition; the taking up into heaven, applied to the Virgin Mary.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (noun) (n.) (noun)
Act of assuming: a supposition.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (noun) (n.) (noun)
The act of assuming; something taken for granted; a supposition.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (noun) (n.) (noun)

Usage examples:

His science would have nothing to hope or fear from either assumption
- Evolution by Frank B. Jevons
" Will," she said, with an assumption of calmness and confidence, " I didn't at once catch the drift of what you were saying to Mr. Cleaver, and when I tried to stop you it was because I was all on edge from hearing such a tremendous piece of news.
- The Devil's Garden by W. B. Maxwell
But what a curious assumption for a Jewish thinker to accept, that unless we are immortal, our acts in this world are of no consequence!
- Dreamers of the Ghetto by I. Zangwill