as certainer

[Eng. ascertain; suff. -er.] One who ascertains anything; one who establishes anything beyond the po ibility of reasonable doubt. as-çer-tā'in-ing, pr . par . [ASCERTAIN.] as-çer-tāin-měnt, s . [Eng. ascertain; -ment.] The act of ascertaining; the state of being ascertained. the positive ascertainment of its limit a."Burke: French Revolution.