ADRIANUM (or ADRIATICUM) MARE, (anc. geog.) now the Gulf of Venice, a large bay in the Mediterranean, between Dalmatia, Sclavonia, Greece, and Italy. It is called by the Greeks, Adriaticus; and Adria by the Romans, as Arbiter Adriæ Notus, Hor. Cicero calls it Hadrianum Mare; Virgil has Hadriaticas Undas. It is commonly called Mare Adriaticum, without an aspiration; but whether it ought to have one, is a dispute: if the appellation is from Hadria, the town of the Piceni, it must be written Hadriaticum, because the emperor's name, who thence derives his origin, is on coins and stones Hadrianus; but if from the town in the territory of Venice, as the more ancient, and of which that of the Piceni is a colony, this will justify the common appellation Adriaticum.