Source : Webster's Revised Unabridged Dictionary (1913)

Galactic \Ga*lac"tic\, a. [Gr. ? milky, fr. ?, ?, milk. See
   {Galaxy}, and cf. {Lactic}.]
   1. Of or pertaining to milk; got from milk; as, galactic
      acid.

   2. Of or pertaining to the galaxy or Milky Way.

   {Galactic circle} (Astron.), the great circle of the heavens,
      to which the course of the galaxy most nearly conforms.
      --Herschel.

   {Galactic poles}, the poles of the galactic circle.

Source : WordNet®

galactic
     adj 1: of or relating to a galaxy (especially our galaxy the Milky
            Way); "the galactic plane"
     2: inconceivably large [syn: {astronomic}, {astronomical}]