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:
US non-farm payrolls figures later Friday are in focus as traders try to ascertain the Fed's next move after last month's rate hike.
From Barron's ● Oct. 2, 2026
L.A. attorney Brian Claypool, who handles wrongful death litigation, said the autopsy and toxicology results “will be crucial in this tragic death to ascertain legal liability.”
From Los Angeles Times ● Sep. 23, 2026
“He was nearby on the scene there, and we were working trying to ascertain his identity and the motivations behind that,” Hicks said.
From The Wall Street Journal ● Aug. 2, 2026
“We are working to ascertain his identity and the motivations.”
From Los Angeles Times ● Aug. 2, 2026
No one, so far as Bloom could ascertain, bore a grudge against Shorty.
From "The Milagro Beanfield War" by John Nichols
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
Ethical philosophy ascertains means of testing the actually existing ideas of morality, and thus enables us to better law and custom.
From A Review of the Systems of Ethics Founded on the Theory of Evolution by C. M. Williams
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
The study suggested that the current outbreak is "larger than currently ascertained" and that its "true magnitude remains uncertain".
From BBC ● May 19, 2026
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
Categories, functions, and meanings have to be ascertained empirically, by running little experiments such as substituting a phrase whose category you don’t know for one you do know and seeing whether the sentence still works.
From "The Sense of Style" by Steven Pinker
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
The 1967 Public Health Act already allows for officers to enter "any premises' at all" for the purpose of "ascertaining whether there is, or has been" any breach of the rules.
From BBC ● Oct. 10, 2024
"Studying isolated enzymes is a powerful tool for ascertaining their activity and drawing conclusions about their functional role inside the plant cell," Hart explained.
From Science Daily ● Apr. 24, 2024
“Miss Miggery, my dear, I do not want to appear too forward so early in our acquaintance, but may I inquire, am I right in ascertaining that you have aspirations?”
From "The Tale of Despereaux: Being the Story of a Mouse, a Princess, Some Soup and a Spool of Thread" by Kate DiCamillo
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
