Latin vicenarius, from viceni twenty each + -arius -ary; akin to Latin viginti twenty; akin to Old Irish fiche twenty, Greek eikosi (Doric ϝikati), Sanskrit viṁśati; all from an Indo-European compound whose 1st constituent was an Indo-European word meaning “two” (represented by Sanskrit vi apart), and whose 2d constituent is represented by Latin decem ten
