continuant vs perpetual

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

perpetual

adj
  • Continuing; uninterrupted. 

  • Set up to be in effect or have tenure for an unlimited duration. 

  • Lasting forever, or for an indefinitely long time. 

  • Flowering throughout the growing season. 

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