continuous vs periodic

continuous

adj
  • Such that, for every x in the domain, for each small open interval D about f(x), there's an interval containing x whose image is in D. 

  • Expressing an ongoing action or state. 

  • Not deviating or varying from uniformity; not interrupted; not joined or articulated. 

  • Without stopping; without a break, cessation, or interruption. 

  • Without intervening space; continued. 

  • Such that each open set in the target space has an open preimage (in the domain space, with respect to the given function). 

periodic

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

  • 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. 

  • Having a structure characterized by periodic sentences. 

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