The Collaborative International Dictionary of English v.0.48:

dayspring \day"spring`\ (d[=a]"spr[i^]ng`), n.
   The beginning of the day, or first appearance of light; the
   dawn; hence, the beginning. --Milton.
   [1913 Webster]

         The tender mercy of our God; whereby the dayspring from
         on high hath visited us.                 --Luke i. 78.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dayspring
    n 1: the first light of day; "we got up before dawn"; "they
         talked until morning" [syn: dawn, dawning, morning,
         aurora, first light, daybreak, break of day, break
         of the day, dayspring, sunrise, sunup, cockcrow]
         [ant: sundown, sunset]