dawn vs nychthemeron

dawn

noun
  • The time when the sun rises. 

  • The rising of the sun. 

  • The earliest phase of something. 

  • The morning twilight period immediately before sunrise. 

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

  • To begin to brighten with daylight. 

  • To start to appear or be realized. 

nychthemeron

noun
  • A period of one day and one night, a date: in the West, this is a period of 24 consecutive hours. 

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