θάλασσα
1. "the sea", Hom., etc.; when he uses it of a particular sea, he means "the Mediterranean", opp. to Ὠκεανός; — Hdt. calls the Mediterranean ἥδε ἡ θάλασσα; so, ἡ παρ᾽ ἡμῖν θάλ. Plat.; κατὰ θάλασσαν by "sea", opp. to πεζῇ by land, Hdt.; to κατὰ γῆς, Thuc.:—metaph., κακῶν θ. "a sea" of troubles, Aesch.
2. "a well of salt water", said to be produced by a stroke of Poseidon's trident, in the Acropolis at Athens, Hdt.