The Collaborative International Dictionary of English v.0.48:

Maxillar \Max"il*lar\, Maxillary \Max"il*la*ry\, a. [L.
   maxillaris, fr. maxilla jawbone, jaw: cf. F. maxillaire.]
   1. (Anat.) Pertaining to either the upper or the lower jaw,
      but now usually applied to the upper jaw only. -- n. The
      principal maxillary bone; the maxilla.
      [1913 Webster]

   2. (Zool.) Of or pertaining to a maxilla.
      [1913 Webster]

WordNet (r) 3.0 (2006):

maxillary
    adj 1: of or relating to the upper jaw
    n 1: the jaw in vertebrates that is fused to the cranium [syn:
         upper jaw, upper jawbone, maxilla, maxillary]