second (subs.) Copy link Outline I. In a duelII. Of time • second (subs.): I. In a duel: perh. auctor (promoter, supporter, backer): cf. Smith's Lat. Dict. s. v. No. VII. II. Of time: perh. mōmentum (temporis): v. moment. More precisely, *horae partis sexagesimae sexagesima pars.