em quad vs quadrant

em quad

noun
  • A quad which has a fixed width of 1 em. 

quadrant

noun
  • One fourth of a circle or disc; a sector with an angle of 90°. 

  • One of the four regions of the Cartesian plane bounded by the x-axis and y-axis. 

  • A measuring device with a graduated arc of 90° used in locating an altitude. 

  • One of the four categories of team wins and losses, as categorized by strength of schedule. 

  • One of the four sections made by dividing an area with two perpendicular lines. 

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