Source : Webster's Revised Unabridged Dictionary (1913)

Mitral \Mi"tral\, a. [Cf. F. mitral. See {Miter}.]
   Pertaining to a miter; resembling a miter; as, the mitral
   valve between the left auricle and left ventricle of the
   heart.

Source : WordNet®

mitral
     adj 1: of or relating to or located in or near the mitral valve;
            "mitral insufficiency"
     2: relating to or resembling the miter worn by some clerics