Drumhead

n.
  1. The parchment or skin stretched over one end of a drum.
  2. The top of a capstan which is pierced with sockets for levers used in turning it. See Illust. of Capstan.
    3. Drumhead court-martial (Mil.),
    a summary court-martial called to try offenses on the battlefield or the line of march, when, sometimes, a drumhead has to do service as a writing table.