Source : Webster's Revised Unabridged Dictionary (1913)

Day-star \Day"-star`\ (-st[aum]r`), n.
   1. The morning star; the star which ushers in the day.

            A dark place, until the day dawn, and the day-star
            arise in your hearts.                 --2 Peter i.
                                                  19.

   2. The sun, as the orb of day. [Poetic]

            So sinks the day-star in the ocean bed, And yet anon
            repairs his drooping head, And tricks his beams, and
            with new-spangled ore Flames in the forehead of the
            morning sky.                          --Milton.