abac vs nomogram

abac

noun
  • A nomogram. 

nomogram

verb
  • To represent as a nomogram. 

noun
  • A diagram in which the relationship between three variables is represented by a straight line or curve for each variable; the value of the third variable corresponding to particular values of the first two is obtained by drawing a straight line through the points on the first two curves that represent particular values of the first two variables and noting the point at which the line intersects the third line or curve. 

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