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• assumption
  assumption

  noun

  something taken for granted; a supposition.
• Assumption
  Assumption

  noun

  the taking up of the Virgin Mary (body and soul) into heaven when her earthly life was ended

assumption

American  

[uh-suhmp-shuhn] / əˈsʌmp ʃən /

noun

• assumptions
  plural

1. something taken for granted; a supposition.

   a correct assumption.

   Synonyms:

   theory, postulate, guess, conjecture, hypothesis, presupposition

2. the act of taking for granted or supposing.

   Synonyms:

   presupposition, presumption

3. the act of taking to or upon oneself.

   Synonyms:

   acceptance

4. the act of taking possession of something.

   the assumption of power.

   Synonyms:

   usurpation, appropriation, seizure

5. arrogance; presumption.

   Synonyms:

   gall, forwardness, effrontery

6. the taking over of another's debts or obligations.

7. Ecclesiastical.

   1. (often initial capital letter) the bodily taking up into heaven of the Virgin Mary.

   2. (initial capital letter) a feast commemorating this, celebrated on August 15.

8. Logic. the minor premise of a syllogism.

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assumption ¹ British  

/ əˈsʌmpʃən /

noun

1. the act of taking something for granted or something that is taken for granted

2. an assuming of power or possession of something

3. arrogance; presumption

4. logic a statement that is used as the premise of a particular argument but may not be otherwise accepted Compare axiom

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Assumption ² British  

/ əˈsʌmpʃən /

noun

1. the taking up of the Virgin Mary (body and soul) into heaven when her earthly life was ended

2. the feast commemorating this, celebrated by Roman Catholics on Aug 15

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Pop Culture

—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.

Other Word Forms

Derived Forms

• misassumption
  noun
• nonassumption
  noun
• overassumption
  noun
• preassumption
  noun
• reassumption
  noun
• self-assumption
  noun
• superassumption
  noun
• assumptive
  adjective
• assumptively
  adverb

Inflected Forms

Nouns

• assumptions
  plural

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Etymology

Origin of assumption

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

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Explanation

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.

Example Sentences

See Examples For:

assumption Assumption assumptions

He added that personnel on two-year deployments often brought their families with them on the assumption it was safe.

From Los Angeles Times ● Nov. 14, 2026

It's also clear that when women see action taken, it can encourage others to speak up as well - as it helps counter the widely-held assumption that reporting abuse results in nothing.

From BBC ● Nov. 14, 2026

Published in Biological Conservation, the findings challenge a longstanding assumption about what Europe's wilderness looked like before widespread human intervention.

From Science Daily ● Nov. 7, 2026

One such assumption is that some mathematical operations are easy to solve in one direction, yet hard to reverse.

From The Wall Street Journal ● Nov. 6, 2026

This is exactly the type of asinine assumption Jupiter hates.

From "Odd One Out" by Nic Stone

The sanctuary of the Lavra’s Assumption Cathedral sustained a direct hit.

From The Wall Street Journal ● Jun. 15, 2026

Ms. O'Grady received a bachelor's degree in English from Assumption College and an M.B.A. in financial management from Pace University.

From The Wall Street Journal ● Feb. 8, 2026

Canan has been part of Chesney’s staff for more than a decade, starting at Assumption College in 2014 before later following Chesney to Holy Cross, James Madison and now UCLA.

From Los Angeles Times ● Jan. 2, 2026

Assumption Island, in the western Indian Ocean, possesses little at first glance that would set even the most curious and intrepid traveller's pulse racing.

From BBC ● Sep. 25, 2025

In 1933, Assumption Church had moved out of its quarters in the storefront on Hart Street.

From "Middlesex: A Novel" by Jeffrey Eugenides

It can push us toward panic selling, drive us to make wild assumptions about the world, and even prompt us to take a hard look at our own finances.

From MarketWatch ● Nov. 10, 2026

"These findings challenge longstanding assumptions that certain biomolecules such as hemoglobin cannot survive deep time," Professor Grice said.

From Science Daily ● Nov. 6, 2026

Christina Pascucci, a political commentator and one-time Senate candidate in California, said the midterms "challenge long-held political assumptions" and show that "neither party can afford to take its traditional strongholds for granted".

From BBC ● Nov. 6, 2026

The shift is also challenging longstanding assumptions about what happens when societies turn away from organized religion, researchers say.

From The Wall Street Journal ● Nov. 6, 2026

And again, very simple assumptions would have enormous consequences.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

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Related Words

• acceptance
• belief
• expectation
• guess
• hunch
• hypothesis
• inference
• premise
• presumption
• supposition
• suspicion
• theory

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