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 judge voiced skepticism during the hearing of Brito’s assertion that the article said Trump personally authored, drew and signed the letter.

From The Wall Street Journal ● Oct. 31, 2026

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

Raman’s office didn’t comment on that assertion, but Stahl said that the Bureau of Street Services isn’t funded to repair damaged sidewalks, and the responsibility falls to the adjacent property owners.

From Los Angeles Times ● Oct. 26, 2026

Pub historian Charo Havermans agreed with that assertion.

From BBC ● Oct. 24, 2026

But Pascal’s simple experiment demolished Aristotle’s assertion that nature abhors a vacuum.

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

Luna remains further above the political fray, favoring plain-spoken assertions about his commitment to the rights and safety of county residents, deputies and inmates alike.

From Los Angeles Times ● Oct. 31, 2026

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

In separate documents filed as part of Mountbatten-Windsor's legal challenge against the warrants, he said: "These assertions were no more than speculation."

From BBC ● Oct. 16, 2026

A Bilt spokesperson said Warren’s assertions were “incorrect.”

From Salon ● Sep. 1, 2026

Linton glanced at the memo Terryl had handed him and could see now that it was a set of facts and assertions mirroring what Terryl was telling him—an outline of the case.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

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Related Words

• affirmation
• allegation
• contention
• insistence
• pronouncement

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