ax·​i·​om | \ ˈak-sē-əm How to pronounce axiom (audio) \

Definition of axiom

1 : a statement accepted as true as the basis for argument or inference : postulate sense 1 one of the axioms of the theory of evolution
2 : an established rule or principle or a self-evident truth cites the axiom "no one gives what he does not have"
3 : a maxim widely accepted on its intrinsic merit the axioms of wisdom

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In mathematics or logic, an axiom is an unprovable rule or first principle accepted as true because it is self-evident or particularly useful. “Nothing can both be and not be at the same time and in the same respect” is an example of an axiom. The term is often used interchangeably with postulate, though the latter term is sometimes reserved for mathematical applications (such as the postulates of Euclidean geometry). It should be contrasted with a theorem, which requires a rigorous proof.

Examples of axiom in a Sentence

one of the key axioms of the theory of evolution
Recent Examples on the Web Know that whole axiom about not needing to reinvent the wheel? Chris Cillizza, CNN, 21 Oct. 2021 That was an emerging axiom in the late 20th century, and a more ubiquitous one today. Ted Anthony, ajc, 1 Aug. 2021 Yet Radtke herself isn’t satisfied with the axiom that Internet relationships are fake. Katy Waldman, The New Yorker, 16 July 2021 Investors had long shied away from investing in space — the quickest way to become a millionaire in space, one axiom went, is to start out as a billionaire. Washington Post, 5 Sep. 2021 There’s an axiom in the NFL that the best way to address a weak position is to flood it with players, increasing the odds that at least one of them is going to work out. Kent Somers, The Arizona Republic, 31 Aug. 2021 But in modern mathematics, the existence of infinite sets is simply assumed to be true—postulated as an axiom that does not require proof. Martin Goldstern, Scientific American, 16 Aug. 2021 But with the time-consuming planning and execution that go with restoration projects, there is Florida’s environmental axiom: easy to break and difficult to repair. Kevin Spear,, 20 Aug. 2021 Arendt first distinguishes rational truth (mathematical truth, philosophical truth—anything that can be proven by axiom) from factual truth. Rebecca Panovka, Harper's Magazine, 20 July 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'axiom.' 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 axiom

15th century, in the meaning defined at sense 3

History and Etymology for axiom

Latin axioma, from Greek axiōma, literally, something worthy, from axioun to think worthy, from axios worth, worthy; akin to Greek agein to weigh, drive — more at agent

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The first known use of axiom was in the 15th century

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axiomata media

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Last Updated

2 Nov 2021

Cite this Entry

“Axiom.” Dictionary, Merriam-Webster, Accessed 5 Dec. 2021.

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More Definitions for axiom


ax·​i·​om | \ ˈak-sē-əm How to pronounce axiom (audio) \

Kids Definition of axiom

1 : maxim
2 : a statement thought to be clearly true


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