Wordnet 3.0
ADJECTIVE (2)
1. 
 of or relating to or located in or near the mitral valve; 
- Example: "mitral insufficiency"2. 
 relating to or resembling the miter worn by some clerics; 
The Collaborative International Dictionary of English v.0.48:
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.
   [1913 Webster]
WordNet (r) 3.0 (2006):
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