Easton's Bible Dictionary (1897)
, “the sea of Adria”), the Adriatic Sea, including in Paul’s time the whole of the Mediterranean lying between Crete and Sicily. It is the modern Gulf of Venice, the Mare Superum_ of the Romans, as distinguished from the Mare Inferum_ or Tyrrhenian Sea.
Smith's Bible Dictionary (1863)
more properly A’drias, the Adriatic Sea. (Acts 27:27) The word seems to have been derived from the town of Adria, near the Po. In Paul’s time it included the whole sea between Greece and Italy, reaching south from Crete to Sicily.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
A'DRIA. Acts 27:27. The northern part of the Ionian Sea between Greece, Italy, and Sicily.