ascertain
Americanverb (used with object)
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to find out definitely; learn with certainty or assurance; determine.
to ascertain the facts.
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Archaic. to make certain, clear, or definitely known.
verb
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to determine or discover definitely
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archaic to make certain
Usage
What are other ways to say ascertain?
To ascertain something is to determine it or learn it with certainty or assurance. How is ascertain different from the learn, discover, and detect? Find out on Thesaurus.com.
Other Word Forms
- ascertainable adjective
- ascertainably adverb
- ascertainer noun
- ascertainment noun
- nonascertainable adjective
- nonascertainableness noun
- nonascertainably adverb
- nonascertainment noun
- preascertain verb (used with object)
- preascertainment noun
- unascertainable adjective
- unascertainably adverb
- unascertained adjective
- well-ascertained adjective
Etymology
Origin of ascertain
First recorded in 1400–50; late Middle English, variant of acertain, assertain, from Middle French acertain-, stem of acertener “to make certain”; equivalent to a- 5 + certain
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.
Officials said they are also in communication with authorities to ascertain the cause of death, obtain the complete medical record and review the circumstances surrounding the death.
From Los Angeles Times • Mar. 30, 2026
But there is a suggestion the Italy midfielder is open to leaving St James' Park this summer, with his representatives understood to be scoping out the market to ascertain which clubs may be interested.
From BBC • Mar. 19, 2026
Though not as rare as having a gold medal, becoming a single father via surrogacy is a pretty select distinction—so select, in fact, that it’s hard to ascertain the exact numbers.
From Slate • Feb. 23, 2026
Karlshorst's representative in the assembly of the city-state of Berlin, Ukrainian-born Lilia Usik, has over the past two years been trying to ascertain if the buildings can be seized or possibly used to help Ukraine.
From Barron's • Feb. 8, 2026
“My job was to ascertain if the casualty warranted the risk,” said Kelley.
From "Boots on the Ground: America's War in Vietnam" by Elizabeth Partridge
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.
