assertion

noun

as·​ser·​tion ə-ˈsər-shən How to pronounce assertion (audio)
a-
Synonyms of assertion
: 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

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The assertion that forecasts are unnecessary turns out to be false. — Steve Banker, Forbes.com, 1 July 2026 The outlet added a second law enforcement source familiar with the matter confirmed that assertion. — Liza Esquibias, USA Today, 1 July 2026 That assertion may come as a surprise to people in the United States ahead of its 250th anniversary. — Sarah M.s. Pearsall, The Conversation, 2 July 2026 Ukraine rejects that assertion and Zelenskyy urged Putin last month to hold a one-on-one meeting with him, but the Kremlin leader refused. — Reuters, NBC news, 5 July 2026 See All Example Sentences for assertion

Word History

Etymology

see assert

First Known Use

15th century, in the meaning defined above

Time Traveler
The first known use of assertion was in the 15th century

Phrases Containing assertion

Rhymes for assertion

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Browse Nearby Words

assertible
assertion
assertional
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Cite this Entry

“Assertion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/assertion. Accessed 9 Jul. 2026.

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Kids Definition

assertion

noun
as·​ser·​tion ə-ˈsər-shən How to pronounce assertion (audio)
a-
: the act of asserting
also : something asserted : declaration

More from Merriam-Webster on assertion

Nglish: Translation of assertion for Spanish Speakers

Britannica.com: Encyclopedia article about assertion

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