a. rare–1. [f. L. vīgēnī, var. of vīcēnī: see VICENARY a.] Of or relating to the number twenty.
1837. Whewell, Hist. Induct. Sci. (1857), I. 93. A method of designating the successive numbers … by means of names framed according to the decimal, quinary, or vigenary scale.
