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.
(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.
assumption has been in the language since the 13th century, and was initially confined to a specific ecclesiastical meaning in the Catholic Church. The Latin word on which it is based literally means “the action of being taken up or received,” and in English assumption referred to the taking up into heaven of the Virgin Mary. That meaning still exists today, and in all the meanings it has assumed since then, one can see the common thread running through them is the sense of taking.
One early sense meant “arrogance,” as in this 1814 quote from Sir Walter Scott: “his usual air of haughty assumption.” Arrogance is a taking upon oneself a conviction of self-importance. Later senses arose having to do with the taking on of power or other responsibilities, as in “the assumption of command.”
Probably the most common meaning of assumption in use today is for indicating a supposition, an estimate, a conjecture—that is, something taken for granted. And as any schoolkid knows, presuming to assume can be dangerous, leading us to make, as the saying goes, “an ASS of U and ME!”
—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.
- mis·as·sump·tion, noun
- non·as·sump·tion, noun
- o·ver·as·sump·tion, noun
- pre·as·sump·tion, noun
- re·as·sump·tion, noun
- self-as·sump·tion, noun
- su·per·as·sump·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use assumption in a sentence
Administration officials have told states to be ready to distribute a vaccine or vaccines as early as November on the assumption that one or more would be approved by the Food and Drug Administration by year’s end or early next year.Top health official says states need about $6 billion from Congress to distribute coronavirus vaccine | Lena H. Sun | September 16, 2020 | Washington Post
Biden’s advisers have prioritized planning for vaccine distribution on the assumption that one or more vaccines would be authorized, or close to approval, by early next year.Trump contradicts CDC director on vaccine; Biden says Americans shouldn’t trust Trump | Colby Itkowitz, Felicia Sonmez, John Wagner | September 16, 2020 | Washington Post
If the shifts among women and older voters seen in the Post-ABC poll reflect an actual shift in the electorate — a fair assumption based on a wide range of other state and national polls — that seems very difficult to do.The key shifts in Minnesota and Wisconsin that have improved Biden’s chances of victory | Philip Bump | September 16, 2020 | Washington Post
The IOC’s understanding of risk, he maintained, was based on an assumption of “slow randomness” rather than the “extreme randomness” that the Oxford researchers believe governs the financial risks of hosting the games.
These conclusions are largely based on unfounded assumptions – rather than actual detailed inspections, physical analysis or testing of any of the building systems.Flaws and Assumptions Render 101 Ash St. Assessment Meaningless | Sandor Shapery | September 10, 2020 | Voice of San Diego
The Samaritan guidelines are written around the assumption that suicide is a purely irrational act, an act spurred by illness.Cover-Ups and Concern Trolls: Actually, It's About Ethics in Suicide Journalism | Arthur Chu | January 3, 2015 | THE DAILY BEAST
“It was just another assumption based on a paradigm that marginalizes non-heterosexual people,” he writes.Yep, Korra and Asami Went in the Spirit Portal and Probably Kissed | Melissa Leon | December 25, 2014 | THE DAILY BEAST
It is a reasonable assumption, considering his roots in the Republican Party, in the Marines, and his proud Scots-Irish roots.
The way I film is based on the assumption that the audience is as smart and dumb as I am.Inside The Secret World of London’s National Gallery | Tim Teeman | November 8, 2014 | THE DAILY BEAST
And that appears to have been their operating assumption when the 43 student teachers went missing.
Oddly enough this assumption—the most warrantable of the lot—was the earliest to fall under disrepute.The Unsolved Riddle of Social Justice | Stephen Leacock
Hilda's assumption that the ageing woman had telegraphed for her on inadequate grounds had proved to be quite wrong.Hilda Lessways | Arnold Bennett
Remember that you asked me to answer on the assumption that you had adequate forces at your disposal, and I did so.Gallipoli Diary, Volume I | Ian Hamilton
Baroudi accepted all these attentions with a magnificent indifference that had in it nothing of assumption.Bella Donna | Robert Hichens
The application of this text to the legend of the assumption is obvious, and occupied the first division of the discourse.Journal of a Voyage to Brazil | Maria Graham
British Dictionary definitions for assumption (1 of 2)
the act of taking something for granted or something that is taken for granted
an assuming of power or possession of something
logic a statement that is used as the premise of a particular argument but may not be otherwise accepted: Compare axiom (def. 4)
- assumptive, adjective
- assumptively, adverb
British Dictionary definitions for Assumption (2 of 2)
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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012