Source : Webster's Revised Unabridged Dictionary (1913)

Perseus \Per"se*us\, n. [L., from Gr. ?.]
   1. (Class. Myth.) A Grecian legendary hero, son of Jupiter
      and Dana["e], who slew the Gorgon Medusa.

   2. (Astron.) A consellation of the northern hemisphere, near
      Taurus and Cassiopea. It contains a star cluster visible
      to the naked eye as a nebula.

Source : WordNet®

Perseus
     n 1: (Greek mythology) the son of Zeus who slew Medusa (with the
          help of Athena and Hermes) and rescued Andromeda from a
          sea monster
     2: a conspicuous constellation in the northern hemisphere;
        between Auriga and Cassiopeia and crossed by the Milky Way