midnight vs twelve o’clock

midnight

adj

  • Utterly dark or black. 

noun

  • Twelve o'clock at night exactly. 

  • Synonym of boxcars (“a pair of sixes”) 

  • The middle of the night: the sixth temporal hour, equidistant between sunset and sunrise. 

twelve o’clock

How often have the words midnight and twelve o’clock occurred in a corpus of books? (source: Google Ngram Viewer )