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

Some requests were for DeepSeek’s technology, a finding that bolsters assertions from Congress that the company is in bed with the CCP’s military and spying apparatus. — Hudson Crozier, The Washington Examiner, 3 Oct. 2026

This study gives us a reason, beyond the assertions of law enforcement leaders, to believe the Flock system deserves some credit for San Francisco's drop in car thefts. — Greg Rosalsky, NPR, 2 Oct. 2026

There are more details about his parents, a sojourn into San Francisco’s bustling Chinatown and an assertion of autonomy within the Trask household, of which Lee is an essential part. — Alison Herman, Variety, 1 Oct. 2026

The second type, structural assets, derives value from categorical assertion. — Joseph Byrum, Forbes.com, 1 Oct. 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