What is "heavy sea"

Sea \Sea\ (s[=e]), n. [OE. see, AS. s[=ae]; akin to D. zee, OS. & OHG. s[=e]o, G. see, OFries. se, Dan. s["o], Sw. sj["o], Icel. s[ae]r, Goth. saiws, and perhaps to L. saevus fierce, savage. [root]151a.]

1. One of the larger bodies of salt water, less than an ocean, found on the earth's surface; a body of salt water of second rank, generally forming part of, or connecting with, an ocean or a larger sea; as, the Mediterranean Sea; the Sea of Marmora; the North Sea; the Carribean Sea.

2. An inland body of water, esp. if large or if salt or brackish; as, the Caspian Sea; the Sea of Aral; sometimes, a small fresh-water lake; as, the Sea of Galilee.

3. The ocean; the whole body of the salt water which covers a large part of the globe.

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

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

4. The swell of the ocean or other body of water in a high wind; motion or agitation of the water's surface; also, a single wave; a billow; as, there was a high sea after the storm; the vessel shipped a sea.

5. (Jewish Antiq.) A great brazen laver in the temple at Jerusalem; -- so called from its size.

   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.

6. Fig.: Anything resembling the sea in vastness; as, a sea of glory.
   --Shak.

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

   Note: 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 Beyond 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.