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 would take time, however, to determine who they were, as the commission will need to ascertain whether the identity tags and Kuban shield actually belong to the two soldiers found.
From BBC ● Aug. 12, 2026
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
In a decision log, shown to the inquiry, Sanders recorded the need to liaise with the head of corporate communications, Matthew Jarram, to "ascertain what covenants can be imposed on the press".
From BBC ● Mar. 18, 2026
Before Mark Antony could solicit help from Egypt, he needed to ascertain Cleopatra’s allegiance.
From "Sterling Biographies®: Cleopatra: Egypt's Last and Greatest Queen" by Susan Blackaby
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
The collective efficiency of the Bismarckian idea, as worked out in the German Constitution, promptly ascertains the will of the people, and carries out that will.
From Blood and Iron Origin of German Empire As Revealed by Character of Its Founder, Bismarck by John Hubert Greusel
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
A third person whose injuries had yet to be ascertained was in the process of being brought to hospital.
From Barron's ● Aug. 21, 2026
The cause of the fire is yet to be ascertained.
From BBC ● Jun. 23, 2026
Both Prieur and Mafart had been involved in planning the operation back in Paris—it was Prieur who had first ascertained the ship’s itinerary by calling Lloyd’s of London and posing as a journalist.
From Slate ● Jul. 22, 2025
But no; they ascertained that the smell was coming from their clothes.
From "Typical American" by Gish Jen
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
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.
