The Collaborative International Dictionary of English v.0.48:

Poppit \Pop"pit\, n.
   a small plastic bead with opposed holes and protuberant
   knobs, so shaped that the beads may be fastened to each other
   in chains and detached easily, and can be used to form
   variable-length chains for use as necklaces, bracelets, or
   other ornamental objects. Also called poppet and poppit
   bead.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Poppet \Pop"pet\, n.
   1. See Puppet.
      [1913 Webster]

   2. (Naut.) One of certain upright timbers on the bilge ways,
      used to support a vessel in launching. --Totten.
      [1913 Webster]

   3. (Mach.) An upright support or guide fastened at the bottom
      only.
      [1913 Webster]

   4. same as poppit.
      [PJC]

   Poppet head, Puppet head. See Headstock
      (a) .
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Puppet \Pup"pet\, n. [OE. popet, OF. poupette; akin to F.
   poup['e]e a doll, probably from L. puppa, pupa, a girl, doll,
   puppet. Cf. Poupeton, Pupa, Pupil, Puppy.] [Written
   also poppet.]
   1. A small image in the human form; a doll.
      [1913 Webster]

   2. A similar figure moved by the hand or by a wire in a mock
      drama; a marionette; a wooden actor in a play.
      [1913 Webster]

            At the pipes of some carved organ move,
            The gilded puppets dance.             --Pope.
      [1913 Webster]

   3. One controlled in his action by the will of another; a
      tool; -- so used in contempt. --Sir W. Scott.
      [1913 Webster]

   4. (Mach.) The upright support for the bearing of the spindle
      in a lathe.
      [1913 Webster]

   Puppet master. Same as Puppetman.

   Puppet play, a puppet show.

   Puppet player, one who manages the motions of puppets.

   Puppet show, a mock drama performed by puppets moved by
      wires.

   Puppet valve, a valve in the form of a circular disk, which
      covers a hole in its seat, and opens by moving bodily away
      from the seat while remaining parallel with it, -- used in
      steam engines, pumps, safety valves, etc. Its edge is
      often beveled, and fits in a conical recess in the seat
      when the valve is closed. See the valves shown in Illusts.
      of Plunger pump, and Safety valve, under Plunger,
      and Safety.
      [1913 Webster]

WordNet (r) 3.0 (2006):

poppet
    n 1: a mushroom-shaped valve that rises perpendicularly from its
         seat; commonly used in internal-combustion engines [syn:
         poppet, poppet valve]