continuant vs ongoing

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

ongoing

adj
  • Continuing, permanent, lasting. 

  • Presently or currently happening; being in progress. 

noun
  • Something that is going on; a happening. 

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