Rump /(?)/

Rump

n.
  1. The end of the backbone of an animal, with the parts adjacent; the buttock or buttocks.
  2. Among butchers, the piece of beef between the sirloin and the aitchbone piece. See Illust. of Beef.
  3. The hind or tail end; a fag-end; a remnant. Fig.:
    The Rump abolished the House of Lords, the army abolished the Rump, and by this army of saints Cromwell governed.