The Collaborative International Dictionary of English v.0.48:

Auricle \Au"ri*cle\, n. [L. auricula, dim. of auris ear. See
   Ear.]
   1. (Anat.)
      (a) The external ear, or that part of the ear which is
          prominent from the head.
      (b) The chamber, or one of the two chambers, of the heart,
          by which the blood is received and transmitted to the
          ventricle or ventricles; -- so called from its
          resemblance to the auricle or external ear of some
          quadrupeds. See Heart.
          [1913 Webster]

   2. (Zool.) An angular or ear-shaped lobe.
      [1913 Webster]

   3. An instrument applied to the ears to give aid in hearing;
      a kind of ear trumpet. --Mansfield.
      [1913 Webster]

WordNet (r) 3.0 (2006):

auricle
    n 1: a small conical pouch projecting from the upper anterior
         part of each atrium of the heart [syn: auricle, atrial
         auricle, auricula atrii]
    2: the externally visible cartilaginous structure of the
       external ear [syn: auricle, pinna, ear]