ramus

from WordNet (r) 3.0 (2006)

ramus
    n 1: the posterior part of the mandible that is more or less
         vertical

from The Collaborative International Dictionary of English v.0.48

Ramus \Ra"mus\ (r[=a]"m[u^]s), n.; pl. {Rami} (r[=a]"m[imac]).
   (Nat. Hist.)
   A branch; a projecting part or prominent process; a
   ramification.
   [1913 Webster]