I. “+ adjective
Etymology: post- + frontal
: situated behind the frontal bone or frontal region of the skull or in reptiles the frontal shield ; specifically : indicating a bone behind and above the orbit of which it commonly forms part of the border that is present in many vertebrates and corresponds to the postorbital process of the frontal bone of various birds and mammals
II. noun
: a postfrontal part (as a bone or scale) ; specifically : the sphenotic bone of a fish