dawn vs twilight

dawn

verb
  • To begin to brighten with daylight. 

  • To begin to give promise; to begin to appear or to expand. 

  • To start to appear or be realized. 

noun
  • The rising of the sun. 

  • The earliest phase of something. 

  • The morning twilight period immediately before sunrise. 

  • The time when the sun rises. 

twilight

verb
  • To illuminate faintly. 

noun
  • Any faint light through which something is seen; an in-between or fading condition. 

  • The soft light in the sky seen before the rising and (especially) after the setting of the sun, occasioned by the illumination of the earth’s atmosphere by the direct rays of the sun and their reflection on the earth. 

  • The time when this light is visible; the period between daylight and darkness. 

  • The time when the sun is less than 18° below the horizon. 

adj
  • Pertaining to or resembling twilight; faintly illuminated; obscure. 

How often have the words dawn and twilight occurred in a corpus of books? (source: Google Ngram Viewer )