as·​sump·​tion | \ ə-ˈsəm(p)-shən How to pronounce assumption (audio) \

Definition of assumption

1 : a taking to or upon oneself the assumption of a new position
2 : the act of laying claim to or taking possession of something the assumption of power
3a : an assuming that something is true a mistaken assumption
b : a fact or statement (such as a proposition, axiom (see axiom sense 2), postulate, or notion) taken for granted
4a : the taking up of a person into heaven
b capitalized : August 15 observed in commemoration of the Assumption of the Virgin Mary
5 : the taking over of another's debts

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Examples of assumption in a Sentence

I made the assumption that he was coming, so I was surprised when he didn't show up. He will come home tomorrow. At least, that's my assumption. Many scientific assumptions about Mars were wrong. I'm telling you our arrival time on the assumption that you will check to see whether or not our flight is on time before you come to the airport. Her plan is based on the underlying assumption that the economy will improve in the near future. her assumption of the presidency the buyer's assumption of debt
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Recent Examples on the Web Especially when casting judgement and basing opinions upon pure speculation, assumptions, & LIES. Kathryn Lindsay,, "The Story Behind Victoria F.’s Cancelled Bachelor Magazine Cover," 5 Feb. 2020 The House indictment of Trump is based on two intertwined democratic assumptions: evidence and accountability. Fintan O’toole, The New York Review of Books, "Whatever He Wants," 30 Jan. 2020 But the assumption that those who require government assistance are, or will be, a burden to the United States is misinformed, and potentially damaging to the very economy the policy seeks to protect. Annalisa Merelli, Quartz, "Immigrants who rely on public benefits are actually essential to the US economy," 30 Jan. 2020 That assumption, at least according to one writer, would be wrong. Jeremy Cluff, azcentral, "Pac-12 basketball power rankings: Arizona State over Arizona after split in Oregon?," 16 Jan. 2020 According to the actuary’s forecast, contribution rates will likely remain relatively flat for the foreseeable future if the system continues to achieve average investment returns close to assumption, which is 7.2 percent annually. oregonlive, "Oregon’s public pension fund had a solid year, just in time," 10 Jan. 2020 Especially when casting judgement and basing opinions upon pure speculation, assumptions, & LIES. Lydia Wang,, "There’s Already A Bachelor Scandal This Season & Victoria Fuller Is Fighting Back," 5 Jan. 2020 In particular, physicists had hoped the experiment would refute one fundamental assumption of general relativity: that the laws of gravity are the same for all objects, regardless of their location, speed, and orientation. Sophia Chen, Wired, "How the Extreme Art of Dropping Stuff Could Upend Physics," 2 Jan. 2020 Underlying all this is the assumption, unspoken but widely acknowledged on the Democratic side, that the Republicans in the Senate will vote to acquit Trump, and attention will then switch to the election campaign. John Cassidy, The New Yorker, "Nancy Pelosi Is Dictating the Democrats’ Impeachment Strategy," 10 Dec. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'assumption.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of assumption

13th century, in the meaning defined at sense 4a

History and Etymology for assumption

Middle English, from Late Latin assumption-, assumptio taking up, from Latin assumere — see assume

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Time Traveler for assumption

Time Traveler

The first known use of assumption was in the 13th century

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Statistics for assumption

Last Updated

11 Feb 2020

Cite this Entry

“Assumption.” Dictionary, Merriam-Webster, Accessed 21 Feb. 2020.

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More Definitions for assumption


How to pronounce assumption (audio)

English Language Learners Definition of assumption

: something that is believed to be true or probably true but that is not known to be true : something that is assumed
: the act of beginning a role, duty, etc.
: the act of taking or beginning to have power, control, etc., in a job or situation


as·​sump·​tion | \ ə-ˈsəmp-shən How to pronounce assumption (audio) \

Kids Definition of assumption

1 : the act of taking on the assumption of power
2 : something accepted as true I'm making plans on the assumption that you will be here.

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