discontinuity vs hiatus

discontinuity

noun
  • A lack of continuity, regularity or sequence; a break or gap. 

  • a subterranean interface at which seismic velocities change 

  • A point in the range of a function at which it is undefined or discontinuous. 

hiatus

noun
  • A gap in a series, making it incomplete. 

  • An opening in an organ. 

  • A gap in geological strata. 

  • A syllable break between two vowels, without an intervening consonant. (Compare diphthong.) 

  • An unexpected break from work. 

  • An interruption, break or pause. 

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