The Collaborative International Dictionary of English v.0.48:

Pteron \Pte"ron\, n. [NL., fr. Gr. ? a wing.] (Anat.)
   The region of the skull, in the temporal fossa back of the
   orbit, where the great wing of the sphenoid, the temporal,
   the parietal, and the frontal hones approach each other.
   [1913 Webster]