ascertain
Americanverb (used with object)
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ascertains,
present (3rd person singular)
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ascertained,
past participle, past
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ascertaining
present participle
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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
Derived Forms
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ascertainernoun
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ascertainmentnoun
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nonascertainablenessnoun
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nonascertainmentnoun
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preascertainmentnoun
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preascertainverb (used with object)
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ascertainableadjective
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nonascertainableadjective
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unascertainableadjective
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unascertainedadjective
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well-ascertainedadjective
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ascertainablyadverb
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nonascertainablyadverb
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unascertainablyadverb
Inflected Forms
Participles
Conjugated Forms
Present
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ascertainsimple
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ascertainssimple
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have ascertainedperfect
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has ascertainedperfect
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am ascertainingprogressive
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are ascertainingprogressive
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is ascertainingprogressive
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have been ascertainingperfect progressive
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has been ascertainingperfect progressive
Past
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ascertainedsimple
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had ascertainedperfect
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was ascertainingprogressive
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were ascertainingprogressive
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had been ascertainingperfect progressive
Future
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.
See Examples For:
It's a selling point but it requires additional testing to ascertain whether the bigger windows hold up as well as the smaller ones.
From BBC ● Sep. 15, 2026
On Thursday, a spokesperson for Greek police told the BBC they were awaiting the outcome of the toxicology tests to determine the cause of death and ascertain whether foul play was involved.
From BBC ● Jul. 31, 2026
If the lawmakers wanted to ascertain U.S. policy, they could have asked the State Department.
From The Wall Street Journal ● Jul. 10, 2026
We just never noticed because we kept looking down at our feet, trying to ascertain a way out.
From Salon ● May 30, 2026
One shared the queen’s bed every night, to ascertain she had no other company; the other two slept in an adjoining chamber with the septa who looked over them.
From "A Dance with Dragons" by George R. R. Martin
Henry plays it safe: He ascertains John is gay so shares his chapters via mail.
From Washington Post ● Dec. 29, 2022
On the other hand, logical analysis ascertains whether the premises of an argument support the conclusion.
From Textbooks ● Jun. 15, 2022
“Insikt Group ascertains with high confidence that the top tools on underground forums will continue to change,” the report said.
From Fox News ● Jul. 27, 2019
“The court looks at the impact and the motivation - if it is an ethical violation, if it is an administrative violation - and then ascertains if the punishment fits the crime,” Grevemberg said.
From Washington Times ● Apr. 2, 2018
One of them ascertains the price paid Arnold.
From The Diplomatic Correspondence of the American Revolution Volume 7. by Various
The researchers also assessed severity of CTE and found a connection between high grade CTE and dementia before death, with the latter ascertained by the players' medical notes and interviews with family members.
From Barron's ● Aug. 25, 2026
Officials say their cause of death will be ascertained after a post-mortem examination.
From BBC ● Jul. 22, 2026
We drove alongside some of the vehicles, peered in windows, and ascertained it was nothing.
From Slate ● Oct. 27, 2025
She’s ascertained that she’s not a child and not an adult; not the sick little girl named Marcy who she used to be, nor her maker’s favorite.
From Salon ● Sep. 24, 2025
It must be ascertained that they had been given orders not to fire until our column was within fair range of their weapons.
From "The Astonishing Life of Octavian Nothing, Traitor to the Nation, Volume II: The Kingdom on the Waves" by M.T. Anderson
The return on the S&P 500 isn’t based on picking winners or ascertaining market sentiment.
From The Wall Street Journal ● May 21, 2026
And if you’re brave enough to step deeper into the lot, yet clearly not confident in ascertaining a Golden Pothos from a Pothos N’Joy, a woman with a warm smile will approach you kindly.
From Los Angeles Times ● Mar. 13, 2025
"I am writing this letter to you, with the main purpose of ascertaining your feelings towards a subject well known to both of us," it began.
From BBC ● Feb. 26, 2024
But ascertaining numbers has been stymied by privacy limits that Capasa said the new survey hopes to overcome.
From Seattle Times ● Feb. 21, 2024
In the autumn of 1971 a man used to come to our house, bearing confections in his pocket and hopes of ascertaining the life or death of his family.
From "Interpreter of Maladies" by Jhumpa Lahiri
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.
