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
-
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
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.
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
Investors, investment advisers and government agencies charged with enforcing fiduciary responsibility need reliable independent data to ascertain whether investments achieve their noneconomic goals and promised rates of return.
From The Wall Street Journal • Mar. 16, 2026
Instead, the duty of a judge is to ascertain “what Congress wanted, as best we can ascertain its intent.”
From Slate • Mar. 4, 2026
“Yes; these four evenings have enabled them to ascertain that they both like Vingt-un better than Commerce; but with respect to any other leading characteristic, I do not imagine that much has been unfolded.”
From "Pride and Prejudice" by Jane Austen
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.
