as·​sump·​tion | \ ə-ˈsəm(p)-shən \

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

Two companies, Razor and Wheels, are already testing out seat attachments under the assumption that the ability to sit would open up the micromobility revolution to a wider audience. Andrew J. Hawkins, The Verge, "Electric scooters are inspiring lazy people to get creative," 21 Oct. 2018 In the face of assumptions that someone like him must be irrevocably damaged, Shinoda asks that his self-interest be recognized as bravery. Spencer Kornhaber, The Atlantic, "Mike Shinoda Asks Not to Be Defined by Loss," 21 June 2018 And Barham was pleased to learn that some assumptions about Trump's supporters were wrong. Gary Graff, Billboard, "American Aquarium Tackles Sobriety on 'One Day at a Time': Premiere," 18 May 2018 For the better part of two decades, an important set of assumptions has underwritten our use of the internet. Jacob Silverman, Longreads, "Searching for a Future Beyond Facebook," 2 May 2018 That said, these are all assumptions based on a logic to which Trump might be immune. Jennifer Wright, Harper's BAZAAR, "What Will Actually Happen to Trump?," 19 Dec. 2018 There was an assumption that a lot of those paintings would come to the museum, notably the Hopper. David Gutman, The Seattle Times, "Multimillion-dollar art collection, once promised to SAM, now up for auction at Christie’s," 14 Nov. 2018 Assuming that the lasers have the same efficiency—and that is a big assumption—then those savings will translate into electrical energy savings as well. Chris Lee, Ars Technica, "661Tbps through a single optical fiber: The mind boggles," 1 Aug. 2018 Why this matters is more important now than ever: There's a longstanding assumption that haute couture clients are European, Russian, or Middle Eastern., "A Jolt Of Diversity At Haute Couture — & Why It Matters," 6 July 2018

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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Last Updated

14 Jan 2019

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Time Traveler for assumption

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

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More Definitions for assumption


as·​sump·​tion | \ ə-ˈsəmp-shən \

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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Comments on assumption

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marked by shyness and lack of polish

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