sea east of Italy, from Latin Adriaticus, properly Hadriaticus, from town of Atria/Hatria (modern Adria) in Picenum, near Venice, once a seaport but now more than 12 miles inland. The name is perhaps from atra, neuter of atrum "black," hence "the black city;" or else it represents Illyrian adur "water, sea."

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Definitions of Adriatic from WordNet

Adriatic (n.)
an arm of the Mediterranean between Slovenia and Croatia and Montenegro and Albania on the east and Italy on the west;
Synonyms: Adriatic Sea