[ uh-suhmp-shuh n ]
/ əˈsʌmp ʃən /


Origin of assumption

1250–1300; Middle English assumpcioun, assompcioun, assumsion < Latin assūmptiōn- (stem of assūmptiō), equivalent to assūmpt(us) taken up (past participle of assūmere; see assume) + -iōn- -ion

Related forms

Can be confused

assumption axiom premise presumption

Related Quotations

  • "[T]he assumption that young people are apathetic, the assumption that Republicans won't cross over, the assumption that the wealthy care nothing for the poor and that the poor don't vote, the assumption that African-Americans can't support the white candidate, whites can't support the African-American candidate, blacks and Latinos cannot come together. We are here tonight to say that that is not the America we believe in."
    -Barack Obama South Carolina Democratic Primary Victory Speech American Rhetoric (delivered January 26, 2008)
  • "We had an assumption, and we had that assumption because Saddam Hussein had lied about using WMD and he had lied about getting rid of them."
    -Jonathan Powell Iraq inquiry: Tony Blair got it wrong, says top aide The Telegraph (January 19, 2010)
  • "Wethern's Law of Suspended Judgement: assumption is the mother of all screwups."
    -Mark Mills The Information Officer (2010)

Word story

The word assumption is a great example of how a word can take on new dimensions of meaning over time, while staying true to some aspect of its original sense.
assumption has been in the language since the 13th century, and was initially confined to a specific ecclesiastical meaning in the Catholic Church. The Latin word on which it is based literally means “the action of being taken up or received,” and in English assumption referred to the taking up into heaven of the Virgin Mary. That meaning still exists today, and in all the meanings it has assumed since then, one can see the common thread running through them is the sense of taking.
One early sense meant “arrogance,” as in this 1814 quote from Sir Walter Scott: “his usual air of haughty assumption.” Arrogance is a taking upon oneself a conviction of self-importance. Later senses arose having to do with the taking on of power or other responsibilities, as in “the assumption of command.”
Probably the most common meaning of assumption in use today is for indicating a supposition, an estimate, a conjecture—that is, something taken for granted. And as any schoolkid knows, presuming to assume can be dangerous, leading us to make, as the saying goes, “an ASS of U and ME!”

Popular references

—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. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for assumptions

British Dictionary definitions for assumptions (1 of 2)


/ (əˈsʌmpʃən) /


the act of taking something for granted or something that is taken for granted
an assuming of power or possession of something
arrogance; presumption
logic a statement that is used as the premise of a particular argument but may not be otherwise acceptedCompare axiom (def. 4)

Derived Forms

assumptive, adjectiveassumptively, adverb

Word Origin for assumption

C13: from Latin assūmptiō a taking up, from assūmere to assume

British Dictionary definitions for assumptions (2 of 2)


/ (əˈsʌmpʃən) /

noun Christianity

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