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tr.v. as·cer·tained, as·cer·tain·ing, as·cer·tains
1. To discover with certainty, as through examination or experimentation. See Synonyms at discover.
2. Archaic To make certain, definite, and precise.

[Middle English acertainen, to inform, from Old French acertener, ascertain- : a-, to (from Latin ad-; see ad-) + certain, certain; see certain.]

as′cer·tain′a·ble adj.
as′cer·tain′a·ble·ness n.
as′cer·tain′a·bly adv.
as′cer·tain′ment n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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Something that has been discovered:
The American Heritage® Roget's Thesaurus. Copyright © 2013, 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


[ˌæsəˈteɪnmənt] Ndeterminación f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005
References in classic literature ?
The suffering, whether of martyr or victim, which belongs to every historical advance of mankind, is represented in this way in every town, and by hundreds of obscure hearths; and we need not shrink from this comparison of small things with great; for does not science tell us that its highest striving is after the ascertainment of a unity which shall bind the smallest things with the greatest?
In addition, the higher observed incidence in Oregon may have been a result of greater case ascertainment because hospital discharge data were used rather than physician and laboratory reports.
Projects focusing on any phase of the gene discovery process, from initial patient ascertainment to positional cloning, are appropriate.
These changes were implemented to improve the potential usefulness of birth certificates for timely and systematic population-based ascertainment of FAS and other abnormal conditions of the newborn (3).
BDI castigated the call of journalist Dragan Pavlovik-Latas for "ethnic mobilization of Macedonians," with the ascertainment that he will divide the country along ethnic lines.
Petrova, ex MP from Burgas Region, informed she made the decision after she saw her name in the infamous notebook of the former Chair of Bulgaria's Commission on Prevention and Ascertainment of Conflict of Interest (CPACI), Filip Zlatanov.
As confirmation of this ascertainment is the newest information that municipality of Centar put aside new 6, 6 million euro for new monuments.
The city of Worcester has had a two-year ascertainment period.
Although administrative controls instituted relatively late in this transmission chain reduced the number of contacts for some SARS patients, we cannot exclude the possibility that ascertainment of contacts for patients who did not transmit SARS was incomplete.
(1) would lead to imprecision in case ascertainment and hence a minimal estimate of the risk.
Surveillance for pregnancy-related deaths based only on ascertainment through death certificates underestimates actual deaths (1-7).