tampion

/T AE1 M P IY0 AH0 N/
noun
  1. 1

    A wooden plug, or a metal or canvas cover for the muzzle of a gun, a cannon or other piece of ordnance when not in use; a stopper; a bung.

  2. 2

    A plug for the upper end of an organ pipe.

Source: https://en.wiktionary.org/wiki/tampion