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.
the taking over of another's debts or obligations.
Ecclesiastical.
(often initial capital letter) the bodily taking up into heaven of the Virgin Mary.
(initial capital letter) a feast commemorating this, celebrated on August 15.
Logic. the minor premise of a syllogism.
the act of taking something for granted or something that is taken for granted
an assuming of power or possession of something
arrogance; presumption
logic a statement that is used as the premise of a particular argument but may not be otherwise accepted Compare axiom
the taking up of the Virgin Mary (body and soul) into heaven when her earthly life was ended
the feast commemorating this, celebrated by Roman Catholics on Aug 15
—Assumption persona: A persona is a detailed description of a fictional user (of a product, software program, etc.), based on real-world data. Software engineers and data companies create personas as user models to help build their products. In order to illustrate the utility of using data-driven personas in design, “assumption personas” (personas derived from existing assumptions about users) are used as negative examples showing how assumptions can lead to bad design choices. —Assumption of risk: the name for a defense used in tort law, where the defense argues that the plaintiff took action knowing the risks involved.
First recorded in 1250–1300; Middle English assumpcioun, assompcioun, assumsion, from Latin assūmptiōn- (stem of assūmptiō ), equivalent to assūmpt(us) “taken up” (past participle of assūmere ) + -iōn- noun suffix; see origin at assume, -ion
An assumption is something that you assume to be the case, even without proof. For example, people might make the assumption that you're a nerd if you wear glasses, even though that's not true. Or very nice. From the Latin assumptionem, meaning “a taking or receiving,” assumption was recorded circa 1300 as a noun describing “the reception of the Virgin Mary into heaven.” The word later shook its religious roots and developed into the noun we hear more often today, usually when a person takes something for granted or literally takes possession of something.
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New research has now overturned that assumption, revealing that the artifacts are actually medieval and provide rare insight into the movement of weapons, trade, and military activity across the Mediterranean during the Late Middle Ages.
From Science Daily • Jun. 8, 2026
These stocks are priced on the assumption that memory stays scarce.
From MarketWatch • Jun. 8, 2026
There was no comparison with a national leader like Franklin Roosevelt or, the unspoken assumption, Churchill himself.
From The Wall Street Journal • Jun. 5, 2026
It is a fair assumption they had bought their tickets long in advance - largely because they assumed four-time champion Iga Swiatek, and not Chwalinska, would be competing.
From BBC • Jun. 4, 2026
“When this was first encountered, and I had puzzled over it for all the time I could spare,” Elizebeth wrote, “I decided to make the assumption that it was enciphered code.”
From "The Woman All Spies Fear" by Amy Butler Greenfield
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
