spring gun
    n 1: a gun that is set to fire on any intruder that comes in
         contact with the wire that sets it off [syn: set gun,
         spring gun]

Spring \Spring\, n. [AS. spring a fountain, a leap. See
   Spring, v. i.]
   1. A leap; a bound; a jump.
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            The prisoner, with a spring, from prison broke.
                                                  --Dryden.
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   2. A flying back; the resilience of a body recovering its
      former state by its elasticity; as, the spring of a bow.
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   3. Elastic power or force.
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            Heavens! what a spring was in his arm! --Dryden.
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   4. An elastic body of any kind, as steel, India rubber, tough
      wood, or compressed air, used for various mechanical
      purposes, as receiving and imparting power, diminishing
      concussion, regulating motion, measuring weight or other
      force.
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   Note: The principal varieties of springs used in mechanisms
         are the spiral spring (Fig. a), the coil spring
         (Fig. b), the elliptic spring (Fig. c), the
         half-elliptic spring (Fig. d), the volute spring,
         the India-rubber spring, the atmospheric spring,
         etc.
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   5. Any source of supply; especially, the source from which a
      stream proceeds; an issue of water from the earth; a
      natural fountain. "All my springs are in thee." --Ps.
      lxxxvii. 7. "A secret spring of spiritual joy." --Bentley.
      "The sacred spring whence right and honor streams." --Sir
      J. Davies.
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   6. Any active power; that by which action, or motion, is
      produced or propagated; cause; origin; motive.
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            Our author shuns by vulgar springs to move
            The hero's glory, or the virgin's love. --Pope.
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   7. That which springs, or is originated, from a source; as:
      (a) A race; lineage. [Obs.] --Chapman.
      (b) A youth; a springal. [Obs.] --Spenser.
      (c) A shoot; a plant; a young tree; also, a grove of
          trees; woodland. [Obs.] --Spenser. Milton.
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   8. That which causes one to spring; specifically, a lively
      tune. [Obs.] --Beau. & Fl.
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   9. The season of the year when plants begin to vegetate and
      grow; the vernal season, usually comprehending the months
      of March, April, and May, in the middle latitudes north of
      the equator. "The green lap of the new-come spring."
      --Shak.
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   Note: Spring of the astronomical year begins with the vernal
         equinox, about March 21st, and ends with the summer
         solstice, about June 21st.
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   10. The time of growth and progress; early portion; first
       stage; as, the spring of life. "The spring of the day."
       --1 Sam. ix. 26.
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             O how this spring of love resembleth
             The uncertain glory of an April day. --Shak.
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   11. (Naut.)
       (a) A crack or fissure in a mast or yard, running
           obliquely or transversely.
       (b) A line led from a vessel's quarter to her cable so
           that by tightening or slacking it she can be made to
           lie in any desired position; a line led diagonally
           from the bow or stern of a vessel to some point upon
           the wharf to which she is moored.
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   Air spring, Boiling spring, etc. See under Air,
      Boiling, etc.

   Spring back (Bookbinding), a back with a curved piece of
      thin sheet iron or of stiff pasteboard fastened to the
      inside, the effect of which is to make the leaves of a
      book thus bound (as a ledger or other account or blank
      book) spring up and lie flat.

   Spring balance, a contrivance for measuring weight or force
      by the elasticity of a spiral spring of steel.

   Spring beam, a beam that supports the side of a paddle box.
      See Paddle beam, under Paddle, n.

   Spring beauty.
       (a) (Bot.) Any plant of the genus Claytonia, delicate
           herbs with somewhat fleshy leaves and pretty
           blossoms, appearing in springtime.
       (b) (Zool.) A small, elegant American butterfly (Erora
           laeta) which appears in spring. The hind wings of
           the male are brown, bordered with deep blue; those of
           the female are mostly blue.

   Spring bed, a mattress, under bed, or bed bottom, in which
      springs, as of metal, are employed to give the required
      elasticity.

   Spring beetle (Zool.), a snapping beetle; an elater.

   Spring box, the box or barrel in a watch, or other piece of
      mechanism, in which the spring is contained.

   Spring fly (Zool.), a caddice fly; -- so called because it
      appears in the spring.

   Spring grass (Bot.), vernal grass. See under Vernal.

   Spring gun, a firearm discharged by a spring, when this is
      trodden upon or is otherwise moved.

   Spring hook (Locomotive Engines), one of the hooks which
      fix the driving-wheel spring to the frame.

   Spring latch, a latch that fastens with a spring.

   Spring lock, a lock that fastens with a spring.

   Spring mattress, a spring bed.

   Spring of an arch (Arch.) See Springing line of an arch,
      under Springing.

   Spring of pork, the lower part of a fore quarter, which is
      divided from the neck, and has the leg and foot without
      the shoulder. [Obs.] --Nares.

            Sir, pray hand the spring of pork to me. --Gayton.

   Spring pin (Locomotive Engines), an iron rod fitted between
      the springs and the axle boxes, to sustain and regulate
      the pressure on the axles.

   Spring rye, a kind of rye sown in the spring; -- in
      distinction from winter rye, sown in autumn.

   Spring stay (Naut.), a preventer stay, to assist the
      regular one. --R. H. Dana, Jr.

   Spring tide, the tide which happens at, or soon after, the
      new and the full moon, and which rises higher than common
      tides. See Tide.

   Spring wagon, a wagon in which springs are interposed
      between the body and the axles to form elastic supports.
      

   Spring wheat, any kind of wheat sown in the spring; -- in
      distinction from winter wheat, which is sown in autumn.
      [1913 Webster] Springald
      Springal