Quadratojugal \Quad*ra`to*ju"gal\, a. (Anat.)
   (a) Of or pertaining to the quadrate and jugal bones.
   (b) Of or pertaining to the quadratojugal bone. -- n. The quadratojugal bone.

Quadratojugal bone (Anat.), a bone at the base of the lower jaw in many animals.

Source: Webster's Revised Unabridged Dictionary (1913)