The Collaborative International Dictionary of English v.0.48:

Andromeda \An*drom"e*da\, n. [L., fr. Gr. ?, the daughter of
   Cepheus and Cassiopeia. When bound to a rock and exposed to a
   sea monster, she was delivered by Perseus.]
   1. (Astron.) A northern constellation, supposed to represent
      the mythical Andromeda.
      [1913 Webster]

   2. (bot.) A genus of ericaceous flowering plants of northern
      climates, of which the original species was found growing
      on a rock surrounded by water.
      [1913 Webster] Andromede

WordNet (r) 3.0 (2006):

andromeda
    n 1: broad-leaved evergreen Asiatic shrub with glossy leaves and
         drooping clusters of white flowers [syn: andromeda,
         Japanese andromeda, lily-of-the-valley tree, Pieris
         japonica]
    2: any of several shrubs of the genus Andromeda having leathery
       leaves and clusters of small flowers
    3: (Greek mythology) an Ethiopian princess and daughter of
       Cassiopeia; she was fastened to a rock and exposed to a sea
       monster that was sent by Poseidon, but she was rescued by
       Perseus and became his wife
    4: a constellation in the northern hemisphere between Cassiopeia
       and Pegasus; contains the Andromeda galaxy