turn upon Copy link Outline I. Lit.II. Fig. • turn upon: ; turn on: I. Lit.: expr. by circum or in with simple verb: v. turn, B. II. Fig.: vertor, 3 dep.: the case t.s on a point of law, causa v. in jure, Cic. Brut. 39, 145. Phr.: he t.'d upon him (a pursuer) with fury, in eum magno impetu rediit, Liv. 1, 25, med.: to t. one's back upon prayers, aversor preces, Liv. 3, 12.