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

Lambermont pushed back on the assertion that data centers are squarely to blame for rising electricity bills. —Zach Halaschak, The Washington Examiner, 20 Mar. 2026

The climate-change assertion also has validity, according to the United Nations. —John C. Moritz, Austin American Statesman, 19 Mar. 2026

That simple assertion touches on a sensitive issue for both the conservative and liberal wings of the court. —Los Angeles Times, 19 Mar. 2026

This backlog underscores Patel’s assertion about the accelerating threat. —Adam Ciralsky, Vanity Fair, 19 Mar. 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
• overexertion
• reassertion

Kids Definition

assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting

also : something asserted : declaration