Source : Webster's Revised Unabridged Dictionary (1913)

Spring \Spring\, n. [AS. spring a fountain, a leap. See
   {Spring}, v. i.]
   1. A leap; a bound; a jump.

            The prisoner, with a spring, from prison broke.
                                                  --Dryden.

   2. A flying back; the resilience of a body recovering its
      former state by elasticity; as, the spring of a bow.

   3. Elastic power or force.

            Heavens! what a spring was in his arm! --Dryden.

   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.

   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.

   5. Any source of supply; especially, the source from which a
      stream proceeds; as 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 and honor streams.''
      --Sir J. Davies.

   6. Any active power; that by which action, or motion, is
      produced or propagated; cause; origin; motive.

            Our author shuns by vulgar springs to move The
            hero's glory, or the virgin's love.   --Pope.

   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.

   8. That which causes one to spring; specifically, a lively
      tune. [Obs.] --Beau. & Fl.

   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.

   Note: Spring of the astronomical year begins with the vernal
         equinox, about March 21st, and ends with the summer
         solstice, about June 21st.

   10. The time of growth and progress; early portion; first
       stage. ``The spring of the day.'' --1 Sam. ix. 26.

             O how this spring of love resembleth The uncertain
             glory of an April day.               --Shak.

   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.

   {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) (Zo["o]l.) A small, elegant American butterfly
           ({Erora l[ae]ta}) 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} (Zo["o]l.), 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} (Zo["o]l.), a caddice fly; -- so called because
      it appears in the spring.

   {Spring grass} (Bot.), a vernal grass. See under {Vernal}.

   {Spring gun}, a firearm disharged 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.



   14. (Paint.)
       (a) The representation or reproduction of the effect of
           the atmospheric medium through which every object in
           nature is viewed. --New Am. Cyc.
       (b) Carriage; attitude; action; movement; as, the head of
           that portrait has a good air. --Fairholt.

   15. (Man.) The artificial motion or carriage of a horse.

   Note: Air is much used adjectively or as the first part of a
         compound term. In most cases it might be written
         indifferently, as a separate limiting word, or as the
         first element of the compound term, with or without the
         hyphen; as, air bladder, air-bladder, or airbladder;
         air cell, air-cell, or aircell; air-pump, or airpump.

   {Air balloon}. See {Balloon}.

   {Air bath}.
       (a) An apparatus for the application of air to the body.
       (b) An arrangement for drying substances in air of any
           desired temperature.

   {Air castle}. See {Castle in the air}, under {Castle}.

   {Air compressor}, a machine for compressing air to be used as
      a motive power.

   {Air crossing}, a passage for air in a mine.

   {Air cushion}, an air-tight cushion which can be inflated;
      also, a device for arresting motion without shock by
      confined air.

   {Air fountain}, a contrivance for producing a jet of water by
      the force of compressed air.

   {Air furnace}, a furnace which depends on a natural draft and
      not on blast.

   {Air line}, a straight line; a bee line. Hence

   {Air-line}, adj.; as, air-line road.

   {Air lock} (Hydr. Engin.), an intermediate chamber between
      the outer air and the compressed-air chamber of a
      pneumatic caisson. --Knight.

   {Air port} (Nav.), a scuttle or porthole in a ship to admit
      air.

   {Air spring}, a spring in which the elasticity of air is
      utilized.

   {Air thermometer}, a form of thermometer in which the
      contraction and expansion of air is made to measure
      changes of temperature.

   {Air threads}, gossamer.

   {Air trap}, a contrivance for shutting off foul air or gas
      from drains, sewers, etc.; a stench trap.

   {Air trunk}, a pipe or shaft for conducting foul or heated
      air from a room.

   {Air valve}, a valve to regulate the admission or egress of
      air; esp. a valve which opens inwardly in a steam boiler
      and allows air to enter.

   {Air way}, a passage for a current of air; as the air way of
      an air pump; an air way in a mine.

   {In the air}.
       (a) Prevalent without traceable origin or authority, as
           rumors.
       (b) Not in a fixed or stable position; unsettled.
       (c) (Mil.) Unsupported and liable to be turned or taken
           in flank; as, the army had its wing in the air.

   {To take air}, to be divulged; to be made public.

   {To take the air}, to go abroad; to walk or ride out.

Source : WordNet®

air spring
     n : a mechanical device using confined air to absorb the shock
         of motion [syn: {air cushion}]