Source : Webster's Revised Unabridged Dictionary (1913)

Arcturus \Arc*tu"rus\, n. [L. Arcturus, Gr. ? bearward, equiv.
   to ?; ? bear + ? ward, guard. See {Arctic}.] (Anat.)
   A fixed star of the first magnitude in the constellation
   Bo["o]tes.

   Note: Arcturus has sometimes been incorrectly used as the
         name of the constellation, or even of Ursa Major.

               Canst thou guide Arcturus with his sons [Rev.
               Ver.: ``the Bear with her train'']. --Job
                                                  xxxviii. 32.

Source : WordNet®

Arcturus
     n : the 4th brightest star and the brightest star in the
         constellation Bootes; 36 light-years from Earth