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

The British government is working under the assumption that the couple’s exposure is a consequence of the first attack. Casey Quackenbush, Time, "Nerve Agent That Poisoned Four People in the U.K. Could Remain Active for 50 Years, Police Say," 11 July 2018 Other chefs had turned down the gig under the assumption that the majority black crowd wouldn’t buy the food. New York Times, "Place 19 of 52: A Celebration of African-American Culture in Baltimore," 29 June 2018 Hixon and his team worked under the assumption that the hats were all produced in a similar manner and placed on the moai using the same technique. Jason Daley, Smithsonian, "The Clever Way the Easter Island Statues Got Hats," 13 June 2018 For decades, the free world has operated under the assumption that the United States will act as its leader, using its might to advance not only its own interests but also those of its kindred nations and the international community writ large. Jonah Shepp, Daily Intelligencer, "Trump’s Credibility Problem Is Now America’s," 26 May 2018 Wagner said council members had been operating under the assumption that Schulte would recruit the interim executive director from city government. Bill Turque, kansascity, "KC council moves to gain more control over American Jazz Museum, but disarray remains | The Kansas City Star," 17 May 2018 So far, the administration -- including Defense Secretary James Mattis -- has operated under the assumption that the existing 2001 authorization for use of military force gives legal cover for military operations in Syria and elsewhere. Erik Wasson,, "New War Authorization for U.S. Military Getting Bipartisan Push," 16 Apr. 2018 And doctors have been operating under the assumption that the risks of leaving moderate or severe depression untreated — for both mom and baby — typically outweigh the known risks associated with antidepressants. Julia Belluz, Vox, "We’re beginning to learn how moms’ antidepressants can affect fetuses," 9 Apr. 2018 These projections are made under the assumption that all of these players are going to turn pro. Peter Dawson, star-telegram, "2018 NBA Mock Draft 1.0: Mavs take forward at No. 5, controversial Duke guard | Fort Worth Star-Telegram," 4 Apr. 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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Phrases Related to assumption

on/under/with the assumption

Statistics for assumption

Last Updated

7 Oct 2018

Look-up Popularity

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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lying above or upon

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