periodic vs undisturbed

periodic

adj
  • 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. 

  • Occurring at regular intervals. 

  • 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. 

undisturbed

adj
  • not disturbed or agitated 

  • calm 

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