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
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ascertainableadjective
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ascertainablyadverb
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ascertainernoun
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ascertainmentnoun
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nonascertainableadjective
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nonascertainablenessnoun
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nonascertainablyadverb
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nonascertainmentnoun
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preascertainverb (used with object)
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preascertainmentnoun
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unascertainableadjective
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unascertainablyadverb
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unascertainedadjective
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well-ascertainedadjective
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
Explanation
Ascertain is a verb that means to find out something. You might have to go to the bank to ascertain if there is any money in your account. This is a formal word that often applies to discovering the facts or truth about something through examination or experimentation. Information that is ascertained is certain beyond a doubt. If you want a less formal synonym, use discover.
Vocabulary lists containing ascertain
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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.
That’s what “I Shot Andy Warhol” wants the viewer to ascertain.
From Salon • Apr. 29, 2026
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
Investors are becoming increasingly nervous about problems mounting in the $3 trillion private credit market where some creditworthiness is deteriorating in some sectors and truthful valuations are hard to ascertain.
From The Wall Street Journal • Mar. 12, 2026
He wanted to ascertain if the mute really understood what was said to him.
From "The Heart is a Lonely Hunter" by Carson McCullers
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.
