assertion

American  

[uh-sur-shuhn] / əˈsɜr ʃən /

noun

• assertions
  plural

1. a positive statement or declaration, often without support or reason.

   a mere assertion;

   an unwarranted assertion.

   Synonyms:

   allegation, contention, claim

2. an act of asserting.

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assertion British  

/ əˈsɜːʃən /

noun

1. a positive statement, usually made without an attempt at furnishing evidence

2. the act of asserting

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Other Word Forms

Derived Forms

• misassertion
  noun
• nonassertion
  noun
• overassertion
  noun
• reassertion
  noun
• superassertion
  noun
• assertional
  adjective

Inflected Forms

Nouns

• assertions
  plural

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Etymology

Origin of assertion

1375–1425; late Middle English assercion < Latin assertiōn- (stem of assertiō ). See assert, -ion

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Explanation

An assertion is a declaration that's made emphatically, especially as part of an argument or as if it's to be understood as a statement of fact. To assert is to state with force. So if someone makes an assertion, they’re not just trying out an idea — they really mean it. An assertion can also be an act that seems to make a statement without words. When your dog urinates in multiple places up and down your block, he's making an assertion of his dominance (also called "marking") over his "territory."

Example Sentences

See Examples For:

assertion assertions

The owner of the building, the Canadian asset manager Brookfield, rejected that assertion, saying it does not have any outstanding sums due to BHV Marais.

From Barron's ● Oct. 27, 2026

Pub historian Charo Havermans agreed with that assertion.

From BBC ● Oct. 24, 2026

Darcy’s sources said Weiss’ objections were not confined to a single factual assertion but ranged far more broadly, and that some on the team were unsure the report would even air at all.

From Salon ● Oct. 20, 2026

As she says it, though, Jeon and co-star Cho Yeo-jeong are laughing — making the assertion rather harder to believe when it arrives in English from Korean via an interpreter.

From Los Angeles Times ● Sep. 6, 2026

The assertion was remarkable partly for being so arrestingly specific but even more for flying in the face of accepted wisdom about the age of the Earth.*

From "A Short History of Nearly Everything" by Bill Bryson

The repeated assertions at the top of the prospectus that “our co-founders have each pledged to dedicate 80% of their personal equity in Anthropic to philanthropic causes” are effectively meaningless.

From MarketWatch ● Oct. 26, 2026

Meanwhile, Britain’s Labour government stalled on corroborating its ally’s assertions while Labour held its annual conference and rallied to a new prime minister, Andy Burnham.

From The Wall Street Journal ● Oct. 7, 2026

In a statement, a spokesperson for Lineage said the the LAFD’s report backed the company’s assertions.

From Los Angeles Times ● Sep. 23, 2026

Tuchel refuted assertions his decision to recall Palmer and Alexander-Arnold was an admission he'd got his World Cup squad wrong.

From BBC ● Sep. 18, 2026

With the passage of time Kelvin would become more forthright in his assertions and less correct.

From "A Short History of Nearly Everything" by Bill Bryson

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Related Words

• affirmation
• allegation
• contention
• insistence
• pronouncement

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