The Collaborative International Dictionary of English v.0.48:

Utricle \U"tri*cle\, n. [L. utriculus a little womb, a calycle,
   dim. of uter, utris, a bag or bottle made of an animal's
   hide: cf. F. utricule.]
   [1913 Webster]
   1. A little sac or vesicle, as the air cell of fucus, or
      seaweed.
      [1913 Webster]

   2. (Physiol.) A microscopic cell in the structure of an egg,
      animal, or plant.
      [1913 Webster]

   3. (Bot.) A small, thin-walled, one-seeded fruit, as of
      goosefoot. --Gray.
      [1913 Webster]

   4. (Anat.) A utriculus.
      [1913 Webster]

WordNet (r) 3.0 (2006):

utricle
    n 1: a small pouch into which the semicircular canals open [syn:
         utricle, utriculus]