viˈgenary,a.rare—1. [f. L. vīgēnī, var. of vīcēnī: see vicenary a.] Of or relating to the number twenty. 1837Whewell 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.