sea

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The continuous body of salt water covering most of the earth's surface, especially this body regarded as a geophysical entity distinct from earth and sky.
• noun A tract of water within an ocean.
• noun A relatively large body of salt water completely or partially enclosed by land.
• noun A relatively large landlocked body of fresh water.
• noun The condition of the ocean's surface with regard to its course, flow, swell, or turbulence.
• noun A wave or swell, especially a large one.
• noun Something that suggests the ocean in its overwhelming sweep or vastness.
• noun Seafaring as a way of life.
• noun Astronomy A lunar mare.
• idiom (at sea) On the sea, especially on a sea voyage.
• idiom (at sea) In a state of confusion or perplexity; at a loss.

from The Century Dictionary.

• noun An obsolete spelling of see.
• noun The salt waters that cover the greater part of the earth's surface; the ocean.
• noun A great body of salt water; a more or less distinctly limited or landlocked part of the ocean having considerable dimensions.
• noun Any widely extended or overwhelming mass or quantity; an ocean; a flood: as, a sea of difficulties; a sea of upturned faces.
• noun The swell of the ocean, or the direction of the waves: as, there was a heavy sea on; to keep the boat's head to the sea.
• noun A large wave; a billow; a surge: as, to ship a sea.
• noun Out on the ocean, and out of sight of land; hence, in the condition of a mariner who has lost his bearings; in a state of uncertainty or error; astray; wide of the mark; quite wrong: as, you are altogether at sea in your guesses.
• noun By the margin of the sea; on the sea-coast.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun An inland body of water, esp. if large or if salt or brackish; ; sometimes, a small fresh-water lake.
• noun The ocean; the whole body of the salt water which covers a large part of the globe.
• noun 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.
• noun (Jewish Antiq.) A great brazen laver in the temple at Jerusalem; -- so called from its size.
• noun Fig.: Anything resembling the sea in vastness.
• noun upon the ocean; away from land; figuratively, without landmarks for guidance; lost; at the mercy of circumstances.
• noun at the height of flood tide; hence, at the height.
• noun (Law) out of the state, territory, realm, or country.
• noun [Colloq.] half drunk.
• noun a sea in which the waves run high.
• noun a sea characterized by the uniform and steady motion of long and extensive waves.
• noun a sea in which the waves are short, broken, and irregular, so as to produce a tumbling or jerking motion.
• noun to adopt the calling or occupation of a sailor.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A large body of salty water. (Major seas are known as oceans.)
• noun figuratively A large number or quantity; a vast amount.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun anything apparently limitless in quantity or volume
• noun turbulent water with swells of considerable size
• noun a division of an ocean or a large body of salt water partially enclosed by land