The Collaborative International Dictionary of English v.0.48:

Prootic \Pro*["o]"tic\, a. [Pref. pro- + Gr. ?, ?, an ear.]
   (Anat.)
   In front of the auditory capsule; -- applied especially to a
   bone, or center of ossification, in the periotic capsule. --
   n. A prootic bone.
   [1913 Webster]