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Synonyms

assumption

American  
[uh-suhmp-shuhn] / əˈsʌmp ʃən /

noun

  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.


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

"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

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

"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

Other Word Forms

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

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; assume, -ion

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

UBS has an end-of-year gold target of $5,600 per ounce, based primarily on the assumption that investors will continue to want to diversify their portfolios with purchases of the precious metal.

From MarketWatch • Mar. 30, 2026

“The assumption that the incoming ownership group can finance an additional $600 million for Moda Center — which is now a publicly-owned community asset is not possible,” lobbying materials from the Blazers stated.

From Salon • Mar. 30, 2026

“There is this assumption that it is going to get fixed tomorrow.”

From Barron's • Mar. 28, 2026

He’s operating under the assumption that oil could hit $175 a barrel and not go back to double digits until next year.

From The Wall Street Journal • Mar. 27, 2026

But he was making one basic mistake—the assumption that Root would play by the rules.

From "Artemis Fowl" by Eoin Colfer