Source : Webster's Revised Unabridged Dictionary (1913)

Aster \As"ter\, n. (Biol.)
   A star-shaped figure of achromatic substance found chiefly in
   cells dividing by mitosis.

Aster \As"ter\ ([a^]s"t[~e]r), n. [L. aster aster, star, Gr.
   'asth`r star. See {Star}.]
   1. (Bot.) A genus of herbs with compound white or bluish
      flowers; starwort; Michaelmas daisy.

   2. (Floriculture) A plant of the genus {Callistephus}. Many
      varieties (called {China asters}, {German asters}, etc.)
      are cultivated for their handsome compound flowers.

Source : WordNet®

aster
     n 1: any of various chiefly fall-blooming herbs of the genus
          Aster with showy daisylike flowers
     2: star-shaped structure formed in the cytoplasm of a cell
        having fibers like rays that surround the centrosome
        during mitosis