† pȳgĭsĭăcus, a, um, adj. [πυγησιακός (not in use), from πυγή], qs. of or belonging to secret buttock-worship: puellam invitare ad pygisiaca sacra, i. e. to copulation, Petr. S. 140 (al. pygiaca, pygiciaca, in the same signif.).