Valve \Valve\, n. [L. valva the leaf, fold, or valve of a door:
   cf. F. valve.]
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   1. A door; especially, one of a pair of folding doors, or one
      of the leaves of such a door.
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            Swift through the valves the visionary fair
            Repassed.                             --Pope.
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            Heavily closed, . . . the valves of the barn doors.
                                                  --Longfellow.
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   2. A lid, plug, or cover, applied to an aperture so that by
      its movement, as by swinging, lifting and falling,
      sliding, turning, or the like, it will open or close the
      aperture to permit or prevent passage, as of a fluid.
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   Note: A valve may act automatically so as to be opened by the
         effort of a fluid to pass in one direction, and closed
         by the effort to pass in the other direction, as a
         clack valve; or it may be opened or closed by hand or
         by mechanism, as a screw valve, or a slide valve.
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   3. (Anat.) One or more membranous partitions, flaps, or
      folds, which permit the passage of the contents of a
      vessel or cavity in one direction, but stop or retard the
      flow in the opposite direction; as, the ileocolic, mitral,
      and semilunar valves.
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   4. (Bot.)
      (a) One of the pieces into which a capsule naturally
          separates when it bursts.
      (b) One of the two similar portions of the shell of a
          diatom.
      (c) A small portion of certain anthers, which opens like a
          trapdoor to allow the pollen to escape, as in the
          barberry.
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   5. (Zool.) One of the pieces or divisions of bivalve or
      multivalve shells.
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   Air valve, Ball valve, Check valve, etc. See under
      Air. Ball, Check, etc.

   Double-beat valve, a kind of balance valve usually
      consisting of a movable, open-ended, turban-shaped shell
      provided with two faces of nearly equal diameters, one
      above another, which rest upon two corresponding seats
      when the valve is closed.

   Equilibrium valve.
      (a) A balance valve. See under Balance.
      (b) A valve for permitting air, steam, water, etc., to
          pass into or out of a chamber so as to establish or
          maintain equal pressure within and without.

   Valve chest (Mach.), a chamber in which a valve works;
      especially (Steam Engine), the steam chest; -- called in
      England valve box, and valve casing. See Steam
      chest, under Steam.

   Valve face (Mach.), that part of the surface of a valve
      which comes in contact with the valve seat.

   Valve gear, or Valve motion (Steam Engine), the system of
      parts by which motion is given to the valve or valves for
      the distribution of steam in the cylinder. For an
      illustration of one form of valve gear, see Link motion.
      

   Valve seat. (Mach.)
      (a) The fixed surface on which a valve rests or against
          which it presses.
      (b) A part or piece on which such a surface is formed.

   Valve stem (Mach.), a rod attached to a valve, for moving
      it.

   Valve yoke (Mach.), a strap embracing a slide valve and
      connecting it to the valve stem.
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Check \Check\ (ch[e^]k), n. [OE. chek, OF. eschec, F. ['e]chec,
   a stop, hindrance, orig. check in the game of chess, pl.
   ['e]checs chess, through Ar., fr. Pers. sh[=a]h king. See
   Shah, and cf. Checkmate, Chess, Checker.]
   1. (Chess) A word of warning denoting that the king is in
      danger; such a menace of a player's king by an adversary's
      move as would, if it were any other piece, expose it to
      immediate capture. A king so menaced is said to be in
      check, and must be made safe at the next move.
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   2. A condition of interrupted or impeded progress; arrest;
      stop; delay; as, to hold an enemy in check.
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            Which gave a remarkable check to the first progress
            of Christianity.                      --Addison.
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            No check, no stay, this streamlet fears.
                                                  --Wordsworth.
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   3. Whatever arrests progress, or limits action; an obstacle,
      guard, restraint, or rebuff.
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            Useful check upon the administration of government.
                                                  --Washington.
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            A man whom no check could abash.      --Macaulay.
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   4. A mark, certificate, or token, by which, errors may be
      prevented, or a thing or person may be identified; as,
      checks placed against items in an account; a check given
      for baggage; a return check on a railroad.
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   5. A written order directing a bank or banker to pay money as
      therein stated. See Bank check, below.
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   6. A woven or painted design in squares resembling the patten
      of a checkerboard; one of the squares of such a design;
      also, cloth having such a figure.
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   7. (Falconry) The forsaking by a hawk of its proper game to
      follow other birds.
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   8. Small chick or crack.
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   Bank check, a written order on a banker or broker to pay
      money in his keeping belonging to the signer.

   Check book, a book containing blank forms for checks upon a
      bank.

   Check hook, a hook on the saddle of a harness, over which a
      checkrein is looped.

   Check list, a list or catalogue by which things may be
      verified, or on which they may be checked.

   Check nut (Mech.), a secondary nut, screwing down upon the
      primary nut to secure it. --Knight.

   Check valve (Mech.), a valve in the feed pipe of a boiler,
      or other conduit, to prevent the return of the feed water
      or other fluid.

   To take check, to take offense. [Obs.] --Dryden.

   Syn: Hindrance; setback; interruption; obstruction;
        reprimand; censure; rebuke; reproof; repulse; rebuff;
        tally; counterfoil; counterbalance; ticket; draft.
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