adv. or adj. phr. 1. On an ocean voyage; on a journey by ship. They had first met at sea. 2. Out on the ocean; away from land. By the second day the ship was well out at sea. Charles had visited a ship in dock, but he had never been on a ship at sea.
at sea 2 adj. phr. Not knowing what to do; bewildered; confused; lost. The job was new to him, and for a few days he was at sea. When his friends talked about chemistry, Don was at sea, because he did not study chemistry.
Compare: AT A LOSS.