I marvel how the fishes live in the sea. Shak.

Ambiguous between sea and land
The river horse and scaly crocodile. Milton.

He made a molten sea of ten cubits from brim to brim, round in compass, and five cubits the height thereof. 2 Chron. iv. 2.

All the space . . . was one sea of heads. Macaulay.

* Sea is often used in the composition of words of obvious signification; as, sea-bathed, sea-beaten, sea-bound, sea-bred, sea-circled, sealike, sea-nursed, sea-tossed, sea-walled, sea- worn, and the like. It is also used either adjectively or in combination with substantives; as, sea bird, sea-bird, or seabird, sea acorn, or sea-acorn.

At sea, upon the ocean; away from land; figuratively, without landmarks for guidance; lost; at the mercy of circumstances. "To say the old man was at sea would be too feeble an expression." G. W. Cable -- At full sea at the height of flood tide; hence, at the height. "But now God's mercy was at full sea." Jer. Taylor. -- Beyond seas, or Beyond the sea or the seas (Law), out of the state, territory, realm, or country. Wharton. -- Half seas over, half drunk. [Colloq.] Spectator. -- Heavy sea, a sea in which the waves run high. -- Long sea, a sea characterized by the uniform and steady motion of long and extensive waves. -- Short sea, a sea in which the waves are short, broken, and irregular, so as to produce a tumbling or jerking motion. -- To go to sea, to adopt the calling or occupation of a sailor.