cer·​tain·​ty ˈsər-tᵊn-tē How to pronounce certainty (audio)
plural certainties
: something that is certain
: the quality or state of being certain especially on the basis of evidence
Choose the Right Synonym for certainty

certainty, certitude, conviction mean a state of being free from doubt.

certainty and certitude are very close; certainty may stress the existence of objective proof

claims that cannot be confirmed with scientific certainty

, while certitude may emphasize a faith in something not needing or not capable of proof.

believes with certitude in an afterlife

conviction applies especially to belief strongly held by an individual.

holds firm convictions on every issue

Example Sentences

Scientists still do not know with any degree of certainty why the disease spread so quickly. We cannot predict the outcome with absolute certainty. There was no certainty that the package would arrive in time. Her certainty about these complex moral issues is surprising.
Recent Examples on the Web Calls about Nevada races were made later – largely because the results were close in many races and the media could not identify the winners with certainty for several days. Nate Trela, USA TODAY, 30 Nov. 2022 While the precise bone count for a T. rex is not known with certainty, and can vary depending on methodology, some scientists have estimated that a complete skeleton would contain 300 bones, and others 380. Zachary Small, New York Times, 23 Nov. 2022 It's not known with certainty what causes an irruption, although most hypotheses point to either a scarcity or abundance of lemmings, the owl's primary food source on their breeding range. Paul A. Smith, Journal Sentinel, 22 Nov. 2022 An earlier assessment from the State Department also determined that the bullet that killed Abu Akleh was likely fired from an Israeli military position but was too damaged to say with certainty. Isabel Debre, ajc, 15 Nov. 2022 Grizzlies haven’t been spotted with certainty in the North Cascades since 1996, the National Park Service said in a news release. Evan Bush, NBC News, 11 Nov. 2022 But during an interview with CNN, Pelosi said with certainty that the attack on her 82-year-old husband has weighed into her thinking. Lisa Mascaro, Chicago Tribune, 7 Nov. 2022 In absence of a scientific consensus, there is good reason to be skeptical of anyone who claims to know the answer with certainty. Jonathan Osborne, Scientific American, 26 Oct. 2022 The video shows what appears to be a fin sticking out of the water, but there did not appear to be enough evidence to know with certainty. Daniel Victor, BostonGlobe.com, 30 Sep. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'certainty.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


Middle English certeinte, borrowed from Anglo-French certeinté, from certein, certain certain entry 1 + -té -ty

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of certainty was in the 14th century

Dictionary Entries Near certainty

Cite this Entry

“Certainty.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/certainty. Accessed 8 Dec. 2022.

Kids Definition


cer·​tain·​ty ˈsərt-ᵊn-tē How to pronounce certainty (audio)
plural certainties
: something certain
: the quality or state of being or feeling certain

More from Merriam-Webster on certainty

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