early 13c., "moral life and conduct, moral excellence," vertu, from Anglo-Fr. and O.Fr. vertu, from L. virtutem (nom. virtus) "moral strength, manliness, valor, excellence, worth," from vir "man" (see
virile). Phrase by virtue of (early 13c.) preserves alternative M.E. sense
of "efficacy." Wyclif Bible has virtue where K.J.V. uses power. The seven cardinal virtues (early 14c.) were divided into the natural (justice, prudence, temperance, fortitude) and the theological (hope, faith, charity). To make a virtue of a necessity (late 14c.) translates L. facere de necessitate virtutem. [Jerome]