[ad_1] 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.
- to determine or discover definitely
- archaic to make certain
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.