The Collaborative International Dictionary of English v.0.48:

Asterope \As*ter"o*pe\, n. [Gr. ?, lit., lightning.]
   1. (Myth.) One of the Pleiades; -- called also Sterope.
      [Webster 1913 Suppl.]

   2. (Astron.) A double star in the Pleiades (21 k and 22 l
      Pleiadum, of the 5.8 and 6.4 magnitude respectively),
      appearing as a single star of the 5.3 magnitude to the
      naked eye.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Asterope
    n 1: (Greek mythology) one of the 7 Pleiades [syn: Sterope,
         Asterope]
    2: one of the stars in the star cluster Pleiades [syn:
       Sterope, Asterope]