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]