Entry 2 senses · 2 variants Webster, 1913 Millenary · Mil·le·na·ry · IPA a. n. 01 a. Consisting of a thousand; millennial. 1. Consisting of a thousand; millennial. 02 n. The space of a thousand years; a millennium; also, a Millenarian. 1. The space of a thousand years; a millennium; also, a Millenarian. See: Millenarian