Synonyms

ascertain

American

[as-er-tayn] / ˌæs ərˈteɪn /

verb (used with object)

to find out definitely; learn with certainty or assurance; determine.

to ascertain the facts.
Archaic. to make certain, clear, or definitely known.

ascertain British

/ ˌæsəˈteɪn /

verb

to determine or discover definitely
archaic to make certain

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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

Inflected Forms

Participles

Conjugated Forms

Present

Past

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.

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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:

ascertain ascertains ascertained ascertaining

Mejia’s office said in a press release Friday that it needed those details and more “to ascertain the financial status of the 2028 Olympic Games.”

From Los Angeles Times ● Oct. 16, 2026

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

"We ‌cannot ascertain when this ‌will end due to the dynamic weather," Transport Minister Dudy Purwagandhi said in relation to the temporary closures of the affected airports.

From BBC ● Sep. 7, 2026

“We are working to ascertain his identity and the motivations.”

From Los Angeles Times ● Aug. 2, 2026

The hearing reached absurd, numbing proportions as lawyers tried to ascertain Edwards’s algebra grade in a court of law.

From "Friday Night Lights: A Town, A Team, And A Dream" by H.G. Bissinger

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

A little chapel ascertains the spot, but he does no miracles on this arena.

From Blackwood's Edinburgh Magazine, Volume 58, Number 360, October 1845 by Various

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 three women's recorded cause of death is yet to be ascertained, the court was also told.

From BBC ● May 29, 2026

Fire service officials have not ascertained which of the two buildings caught fire first.

From BBC ● Oct. 14, 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 export control amounts to a de facto ban on the model since Anthropic has no way of ascertaining the nationality of its users.

From The Wall Street Journal ● Jun. 16, 2026

On Monday evening, Assam Director General of Police GP Singh had said that authorities were ascertaining the exact number of people trapped.

From BBC ● Jan. 7, 2025

Her petition said they are still ascertaining the assets to be identified as separate and community property.

From Los Angeles Times ● Aug. 27, 2024

“Sourcing gold from the UAE is notoriously risky,” the report said, describing the difficulty in ascertaining the origins of the refined gold.

From Seattle Times ● May 30, 2024

It is desired that the investigation of subject be most searching and pointed towards ascertaining the nature of her present activity and the identity of her associate.

From "Endgame" by Frank Brady

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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023