From Longman Dictionary of Contemporary Englishthe seasthe seasliteraryHAAL the sea – used especially when you are not talking about a particular oceanacross the seas (=far away) They came from lands across the seas. → sea
Examples from the Corpus
the seas• Till a' the seas gang dry, my dear.• The crew was exhausted, the seas still heavy, and without daylight we could not see what we were doing.• The captain too found the seas rougher than his liking.• One-third of the world's human population lives on land that is liable to be inundated if the seas rise.• Who knows what the depths of the seas may yet yield?• On the seas and far away On stormy seas and far away.• The fleets of Ulthuan ranged the seas destroying Dark Elf slaving ships.• First entering shallow equatorial seas, then estuaries and coastal oceans, the prehistoric cetaceans spread through the seas of the world. 