isochronous vs periodic

isochronous

adj
  • Happening at regular intervals; isochronal. 

  • Happening at the same time; simultaneous. 

  • of or pertaining to data associated with time-sensitive applications. 

  • Of or pertaining to the use of clocks derived from the same clock reference. 

periodic

adj
  • Occurring at regular intervals. 

  • Relating to the highest oxidation state of iodine; of or derived from a periodic acid. 

  • Periodical. 

  • Pertaining to the revolution of a celestial object in its orbit. 

  • Relative to a period or periods. 

  • Having repeated cycles. 

  • For which any return to it must occur in multiples of k time steps, for some k>1. 

  • Having a structure characterized by periodic sentences. 

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