Occiput

from WordNet (r) 3.0 (2006)

occiput
    n 1: back part of the head or skull

from The Collaborative International Dictionary of English v.0.48

Occiput \Oc"ci*put\, n.; pl. L. {Occipita}, E. {Occiputs}. [L.,
   fr. ob (see {Ob-}) + caput head. See {Chief}.]
   1. (Anat.) The back, or posterior, part of the head or skull;
      the region of the occipital bone.
      [1913 Webster]

   2. (Zool.) A plate which forms the back part of the head of
      insects.
      [1913 Webster]