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
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.
Mr. Morson, a professor of Slavic languages and literatures at Northwestern University, is the author of “Wonder Confronts Certainty: Russian Writers on the Timeless Questions and Why Their Answers Matter.”
From The Wall Street Journal • Dec. 15, 2025
Certainty has a price, however, in terms of tax rises.
From BBC • Nov. 13, 2025
Certainty about the smallest detectable flaw size allows more design freedom.
From Science Daily • Oct. 26, 2023
Q: Certainty of an encounter with ultimate reality?
From Washington Post • Nov. 10, 2022
For Locke there are ‘three degrees of Knowledge, viz. Intuitive, Demonstrative, and Sensitive: in each of which, there are different degrees and ways of Evidence and Certainty’.
From "The Invention of Science" by David Wootton
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.
