isochronal vs repeatable

isochronal

adj
  • Having the same duration. 

  • Happening at regular periods; isochronous, periodic. 

  • Time-dependent. 

repeatable

adj
  • That gives the same results when repeated 

  • Able to be repeated 

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