disc vs pair of compasses

disc

noun
  • A thin, flat, circular plate or similar object. 

  • A vinyl phonograph / gramophone record. 

  • The flat surface of an organ, as a leaf, any flat, round growth. 

  • An intervertebral disc. 

  • Venus's disc cut off light from the Sun. 

  • Something resembling a disc. 

verb
  • To move towards, or operate at, zero blade pitch, orienting the propeller blades face-on to the oncoming airflow and maximising the drag generated by the propeller. 

  • To harrow with a disc harrow. 

pair of compasses

noun
  • A tool for drawing accurate circles or arches, usually consisting of two arms joined at one end in such a way that the arms can be opened and closed; one of the arms is pointed at its free end while the other holds a pencil, pencil lead or some other implement for making marks. 

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