[ as-er-teyn ]
/ ˌæs ərˈteɪn /
Save This Word!
See synonyms for: ascertain / ascertained / ascertaining / ascertainable on Thesaurus.com

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.



Apostrophes can be tricky; prove you know the difference between it’s and its in this crafty quiz!
Question 1 of 12
On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

Origin of ascertain

1400–50; late Middle English, variant of assertain, acertain<Middle French acertain- (tonic stem of acertener to make certain), equivalent to a-a-5 + certaincertain
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for ascertain

/ (ˌæsəˈteɪn) /

verb (tr)

to determine or discover definitely
archaic to make certain
ascertainable, adjectiveascertainably, adverbascertainment, noun
C15: from Old French acertener 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
Hate Typos? Get Grammar Coach