assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting or something that is asserted: such as

a

: insistent and positive affirming, maintaining, or defending (as of a right or attribute)

an assertion of ownership/innocence

b

: a declaration that something is the case

He presented no evidence to support his assertions.

Synonyms of assertion

• declaration
• claim
• insistence
• allegation

Examples of assertion in a Sentence

the assertion that all men have certain unalienable rights is set forth in the Declaration of Independence

made the unlikely assertion that gravity affects light

Recent Examples on the Web

The journal retracted the study in 2010 and the author, who lost his medical license because of his assertion, has never been able to replicate his findings. — Mary Kekatos, ABC News, 13 Aug. 2026

Across the globe, anti-gender campaigning is frequently tied to right-wing nationalism, white supremacy, and assertions of patriarchal power. — Literary Hub, 13 Aug. 2026

Continue reading … DEFENSIVE STANCE – Controversial WNBA player pushes back on Sophie Cunningham's assertion on hard foul. — FOXNews.com, 11 Aug. 2026

Unless the resulting answer, known as an authentication assertion, is signed by the private key stored safely in the TPM or secure enclave, the assertion is rejected. — Dan Goodin, ArsTechnica, 11 Aug. 2026

Word History

Etymology

see assert

First Known Use

15th century, in the meaning defined above

Phrases Containing assertion

• self-assertion

Rhymes for assertion

• cistercian
• coercion
• desertion
• exertion
• insertion
• mercian
• tertian
• overexertion
• reassertion

Kids Definition

assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting

also : something asserted : declaration