The Collaborative International Dictionary of English v.0.48:

Zygoma \Zy*go"ma\, n. [NL., fr. Gr. ?, fr. ? to yoke, zygo`n a
   yoke.] (Anat.)
   (a) The jugal, malar, or cheek bone.
   (b) The zygomatic process of the temporal bone.
   (c) The whole zygomatic arch.
       [1913 Webster]

WordNet (r) 3.0 (2006):

zygoma
    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]