c. 1200, dauen, "to become day, grow light in the morning," shortened or back-formed from dauinge, dauing "period between darkness and sunrise," (c. 1200), from Old English dagung, from dagian "to become day," from Proto-Germanic *dagaz "day" (source also of German tagen "to dawn"), from PIE root *agh- "a day." Probably influenced by Scandinavian cognates (Danish dagning, Old Norse dagan "a dawning"). Related: Dawned; dawning.
Figurative sense "begin to develop" is from 1717. Of ideas, etc., "begin to become apparent or evident to the mind," by 1852.
1590s, "first appearance of daylight in the morning," from dawn (v.). Middle English words for "first appearance of light in the morning" were day-gleam (late 14c.), dayspring (c. 1300), and dawning. Dawn (n.) in the figurative sense of "first opening or expansion of anything" is from 1630s. As a fem. proper name, little used in U.S. before 1920 but a top 25 name for girls born 1966-1975.