compass vs sigmoid

compass

verb
  • To surround; to encircle; to environ; to stretch round. 

  • To go about or round entirely; to traverse. 

noun
  • A pair of compasses (a device used to draw an arc or circle). 

  • A magnetic or electronic device used to determine the cardinal directions (usually magnetic or true north). 

  • The range of notes of a musical instrument or voice. 

  • Moderate bounds, limits of truth; moderation; due limits; used with within. 

sigmoid

adj
  • Relating to the sigmoid colon. 

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

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

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