backbench

from WordNet (r) 3.0 (2006)

backbench
    n 1: any of the seats occupied by backbenchers in the House of
         Commons

from The Collaborative International Dictionary of English v.0.48

backbench \back"bench\ (b[a^]k"b[e^]nch), n.
   1. any of the seats occupied by backbenchers in the House of
      Commons of Great Britain.
      [WordNet 1.5]