breathing space vs hiatus

breathing space

noun
  • A rest, pause, or respite. 

  • Enough distance so that one can feel unfettered. 

  • Sufficient space or a span of time in which to recover one's breath. 

hiatus

noun
  • An interruption, break or pause. 

  • 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. 

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