sigmoid vs sinuous

sigmoid

adj
  • Curved in two directions, like the letter "S", or the Greek ς (sigma); having a serpentine shape. 

  • Relating to the sigmoid colon. 

  • Exhibiting logistic growth; having a graph that accelerates until it reaches a carrying capacity. 

sinuous

adj
  • Having curves in alternate directions; meandering. 

  • Moving gracefully and in a supple manner. 

  • Morally crooked; shifty. 

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