ascertain

verb

as·​cer·​tain ˌa-sər-ˈtān How to pronounce ascertain (audio)
ascertained; ascertaining; ascertains

transitive verb

1
: to find out or learn with certainty
ascertain the truth
trying to ascertain the cause of the fire
information that can be easily ascertained on the Internet
2
archaic : to make certain, exact, or precise
ascertainable adjective
ascertainment noun
Choose the Right Synonym for ascertain

discover, ascertain, determine, unearth, learn mean to find out what one did not previously know.

discover may apply to something requiring exploration or investigation or to a chance encounter.

discovered the source of the river

ascertain implies effort to find the facts or the truth proceeding from awareness of ignorance or uncertainty.

attempts to ascertain the population of the region

determine emphasizes the intent to establish the facts definitely or precisely.

unable to determine the origin of the word

unearth implies bringing to light something forgotten or hidden.

unearth old records

learn may imply acquiring knowledge with little effort or conscious intention (as by simply being told) or it may imply study and practice.

I learned her name only today
learning Greek

Examples of ascertain in a Sentence

We look at digital media—images, audio and video—and we try to ascertain whether or not they've been manipulated. We use mathematical and computational techniques to detect alterations in them. Claudia Dreifus, New York Times, 2 Oct. 2007
Currently, an official trying to ascertain road damage in the aftermath of an earthquake might have to keep one eye on the TV news while listening to both radio traffic reports and the police scanner. Since most of these data are available in digital form, the software could take them all in, process them and present a report outlining the best evacuation routes. Kevin Hogan, Technology Review, April 2002
With an equation linking the money wage to prices, the degree of inflation could be ascertained. Sidney Weintraub, Modern Economic Thought, (1977) 1993
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This concentration was then used to ascertain the time-dependent effect of both cannabinoids. Paul McClure 14, New Atlas, 14 June 2025 Chemist Willard Libby developed this method — used to ascertain the age of organic materials — in the late 1940s at the University of Chicago. Jacopo Prisco, CNN Money, 7 June 2025 The states are particularly worried about how to ascertain citizenship when a new resident comes from another state, according to Noah Purcell, solicitor general for the state of Washington. Nina Totenberg, NPR, 15 May 2025 While buyers and sellers involved in the transaction could not be immediately ascertained, CNBC-TV18, citing sources familiar with the matter, noted that South Korean automaker Hyundai Motor Company was likely among the sellers in the deal. Amala Balakrishner, CNBC, 2 June 2025 See All Example Sentences for ascertain

Word History

Etymology

Middle English acertainen to inform, give assurance to, from Anglo-French acerteiner, from a- (from Latin ad-) + certein, certain certain

First Known Use

15th century, in the meaning defined at sense 2

Time Traveler
The first known use of ascertain was in the 15th century

Browse Nearby Words

Cite this Entry

“Ascertain.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ascertain. Accessed 24 Jun. 2025.

Kids Definition

ascertain

verb
as·​cer·​tain ˌas-ər-ˈtān How to pronounce ascertain (audio)
: to learn with certainty : find out
could not ascertain the correct date
ascertainable adjective
ascertainment noun

More from Merriam-Webster on ascertain

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