The Collaborative International Dictionary of English v.0.48:

Odontoid \O*don"toid\, a. [Gr. ?; 'odoy`s, 'odo`ntos, a tooth +
   e'i^dos form: cf. F. odonto["i]de.] (Anat.)
   (a) Having the form of a tooth; toothlike.
   (b) Of or pertaining to the odontoid bone or to the odontoid
       process.
       [1913 Webster]

   Odontoid bone (Anat.), a separate bone, in many reptiles,
      corresponding to the odontoid process.

   Odontoid process, or Odontoid peg (Anat.), the anterior
      process of the centrum of the second vertebra, or axis, in
      birds and mammals. See Axis.
      [1913 Webster]

WordNet (r) 3.0 (2006):

odontoid process
    n 1: a toothlike process at the back of 2nd vertebra of the neck