certainty
Americannoun
-
the state of being certain.
- Synonyms:
- confidence, assurance, certitude
-
something certain; an assured fact.
- Synonyms:
- truth
idioms
noun
-
the condition of being certain
-
something established as certain or inevitable
-
without doubt
Synonym Usage
See belief.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of certainty
1250–1300; Middle English certeinte < Anglo-French, equivalent to certein certain + -te -ty 2
Explanation
A certainty is a sure thing, something we know is true or will happen without any doubt. Here's a certainty: One plus one is two. And here's another: The earth orbits the sun. The noun certainty comes from the Latin word certus, meaning "sure" or "fixed." Besides being something that is certain, the word can also refer to a state of mind, like the confidence you feel when you know something is completely true or right. For example, you might speak with certainty about your decision to move to the big city and pursue your dream of becoming a famous actor. (But that doesn't necessarily mean becoming a famous actor is a certainty.)
Vocabulary lists containing certainty
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
"After the weather delay we saw before the Mexico game, we want to give fans and venues complete certainty that no-one will miss a moment of the action."
From BBC ● Jul. 11, 2026
Even so, scientists still cannot say with certainty which volcanic feature is erupting, how deep the active vent originally was, or when it last erupted.
From Science Daily ● Jul. 10, 2026
Humanoids tasked with performing multiple jobs use artificial intelligence and are “probabilistic,” meaning they operate on statistical likelihoods, not certainty.
From The Wall Street Journal ● Jul. 4, 2026
That certainty is now in question, at exactly the wrong time.
From Barron's ● Jun. 30, 2026
Thus I have moral certainty that Caesar crossed the Rubicon, and moral certainty that Pascal accurately reported the Puy-de-Dôme experiment.
From "The Invention of Science" by David Wootton
Death, taxes and Jean Smart winning another Emmy are among life’s certainties.
From Los Angeles Times ● Jul. 7, 2026
These calculations are useful, but they are estimates rather than certainties.
From MarketWatch ● May 26, 2026
To death and taxes, add Red Rose victories to life's certainties.
From BBC ● May 17, 2026
AI systems produce probabilities, and people treat them as certainties.
From Salon ● May 12, 2026
Rhetoric deals with probabilities rather than certainties: with analogy and generalization.
From "Words Like Loaded Pistols" by Sam Leith
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
