sleeper

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

• noun One that sleeps.
• noun A sleeping car.
• noun Children's pajamas, usually with legs that cover the feet.
• noun One that achieves unexpected recognition or success, as a racehorse or movie.
• noun A spy or saboteur who is planted in an enemy country and who lives unobtrusively as a citizen of that country until activated into clandestine operations by a prearranged signal.
• noun A horizontal structural member on or near the ground that supports weight.
• noun Chiefly British A railroad crosstie.
• noun Any of various chiefly tropical fishes of the family Eleotridae of fresh, brackish, and shallow marine waters, resembling the gobies but without fused pelvic fins and noted for their habit of lying immobile.

from The Century Dictionary.

• noun A stump of a tree cut off short and left In the ground.
• noun A beam of wood or the like placed on the ground as a support for something.
• noun In ship-building, a thick piece of timber placed longitudinally in a ship's hold, opposite the several scarfs of the timbers, for strengthening the bows and stern-frame; a piece of long compass-timber fayed and bolted diagonally upon the transoms.
• noun In glass-making, one of the large iron bars crossing the smaller ones, which hinder the passage of coals, but leave room for the ashes.
• noun In weaving, the upper part of the heddle of a draw-loom, through which the threads pass.
• noun In faro, a bet left upon a card which the case-keeper shows is dead. Such a bet is public property and the first one to see it can take it.
• noun One who sleeps: as, a sound sleeper.
• noun A drone, or lazy person; a sluggard.
• noun A dormant or inoperative thing; something that is in abeyance or is latent.
• noun An animal that lies dormant in winter or summer, as the bear, the marmot, certain mollusks, etc. See sleep, n., 4.
• noun Figuratively, a dead person.
• noun plural Grains of barley that do not vegetate in malting.
• noun A railway sleeping-car.
• noun In zoology:
• noun The dormouse, Myoxus avellanarius.
• noun The sleeper-shark, Somniosus microcephalus, and some related species, as Ginglymostoma cirratum.
• noun A gobioid fish of the genus Philypnus, Eleotris, or Dormitator, as D. lineatus or D. maculatus. See Elcotridinæ.

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

• noun One who sleeps; a slumberer; hence, a drone, or lazy person.
• noun obsolete That which lies dormant, as a law.
• noun Colloq. U.S. A sleeping car.
• noun (Zoöl.) An animal that hibernates, as the bear.
• noun A large fresh-water gobioid fish (Eleotris dormatrix).
• noun A nurse shark. See under Nurse.
• noun Something lying in a reclining posture or position.
• noun One of the pieces of timber, stone, or iron, on or near the level of the ground, for the support of some superstructure, to steady framework, to keep in place the rails of a railway, etc.; a stringpiece.
• noun U.S. One of the joists, or roughly shaped timbers, laid directly upon the ground, to receive the flooring of the ground story.
• noun (Naut.) One of the knees which connect the transoms to the after timbers on the ship's quarter.
• noun (Naut.) The lowest, or bottom, tier of casks.

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

• noun rail transport, UK A railroad tie. The short wooden bars are sleepers, and the long metal bars are railway lines.
• noun carpentry A structural beam in a floor running perpendicular to both the joists beneath and floorboards above.
• noun nautical A heavy floor timber in a ship's bottom.
• noun nautical The lowest, or bottom, tier of casks.
• noun Someone who sleeps.
• noun A spy, saboteur, or terrorist who lives unobtrusively in a community until activated by a prearranged signal; may be part of a sleeper cell.
• noun A railroad sleeping car.
• noun Something that achieves unexpected success after an interval of time.
• noun A goby-like bottom-feeding freshwater fish of the family Odontobutidae. Also "sleeper goby."
• noun A type of pajama for a person, especially a child, that covers the whole body, including the feet.
• noun An automobile which, not too quick out of the factory has been internally modified to excess, while retaining a mostly stock appearance in order to fool opponents in a drag race.

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

• noun a passenger car that has berths for sleeping