[1] : The Collaborative International Dictionary of English v.0.48

tampion \tam"pion\, n. f. tampon, tapon, tape, of dutch or
   german origin. see tap a pipe or plug, and cf. tamp,
   tampop, tompion. written also tampeon, and
   tompion.
   1. a wooden stopper, or plug, as for a cannon or other piece
      of ordnance, when not in use.
      1913 webster

   2. mus. a plug for upper end of an organ pipe.
      1913 webster
see also:
tap tamp tampop tompion tampeon tompion 

[2] : WordNet (r) 2.0

tampion
     n : plug for the muzzle of a gun to keep out dust and moisture

Tampion >> T Words
Tampion, definition of term: Tampion
tampion_pag1.html