The Collaborative International Dictionary of English v.0.48:

Zygomatic \Zyg`o*mat"ic\ (?; 277), a. [Cf. F. zygomatique.]
   (Anat.)
   Of, pertaining to, or in the region of, the zygoma.
   [1913 Webster]

   Zygomatic arch, the arch of bone beneath the orbit, formed
      in most mammals by the union of the malar, or jugal, with
      the zygomatic process of the temporal bone. In the lower
      vertebrates other bones may help to form it, and there may
      be two arches on each side of the skull, as in some
      reptiles.

   Zygomatic process, a process of the temporal or squamosal
      bone helping to form the zygomatic arch.
      [1913 Webster] Zygomorphic

WordNet (r) 3.0 (2006):

zygomatic arch
    n 1: the slender arch formed by the temporal process of the
         cheekbone that bridges to the zygomatic process of the
         temporal bone [syn: zygoma, zygomatic arch, arcus
         zygomaticus]