verb as·cer·tain \ˌa-sər-ˈtān\

Definition of ascertain

  1. transitive verb
  2. 1 archaic :  to make certain, exact, or precise

  3. 2 :  to find out or learn with certainty


play \-ˈtā-nə-bəl\ adjective


play \-ˈtān-mənt\ noun

Examples of ascertain in a sentence

  1. 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

  2. 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

  3. With an equation linking the money wage to prices, the degree of inflation could be ascertained. —Sidney Weintraub, Modern Economic Thought, (1977) 1993

  4. The information can be ascertained by anyone with a computer.

  5. <was immediately able to ascertain that the girl was uncomfortable talking about her life at home>

Origin and Etymology of ascertain

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

Synonym Discussion of 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>.

ASCERTAIN Defined for English Language Learners


verb as·cer·tain \ˌa-sər-ˈtān\

Definition of ascertain for English Language Learners

  • : to learn or find out (something, such as information or the truth)

ASCERTAIN Defined for Kids


verb as·cer·tain \ˌa-sər-ˈtān\

Definition of ascertain for Students



  1. :  to find out with certainty <Police tried to ascertain the cause of the accident.>

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