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Supposedly vs. Supposably


[as-er-teyn] /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.
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 + certain certain
Related 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
Synonym Study
1. See learn. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for ascertain
Contemporary Examples
Historical Examples
  • The trapper looked about him to ascertain in what situations he might find his friends.

    The Prairie J. Fenimore Cooper
  • All efforts to ascertain your fate proved utterly fruitless.

    Philothea Lydia Maria Child
  • Carley searched her pockets for her goggles, only to ascertain that she had forgotten them.

  • They appraised me in their own minds, I saw, and were curious to ascertain what my full value was.

    Little Dorrit Charles Dickens
  • To ascertain how much power has been developed we must know how many foot pounds there are in a horse power.

    Motors James Slough Zerbe
British Dictionary definitions for ascertain


verb (transitive)
to determine or discover definitely
(archaic) to make certain
Derived Forms
ascertainable, adjective
ascertainably, adverb
ascertainment, noun
Word Origin
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
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Word Origin and History for ascertain

early 15c., "to inform, to give assurance," from Anglo-French acerteiner, Old French acertener "to assure, certify" (13c.), from a "to" (see ad-) + certain "certain" (see certain). Modern meaning of "find out for sure by experiment or investigation" is first attested 1794. Related: Ascertained; ascertaining.

Online Etymology Dictionary, © 2010 Douglas Harper
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