Orthognathous \Or*thog"na*thous\, a. [Ortho- + Gr. gna`qos the
jaw.] (Anat.)
Having the front of the head, or the skull, nearly
perpendicular, not retreating backwards above the jaws; --
opposed to {prognathous}. See {Gnathic index}, under
{Gnathic}.
[1913 Webster]