diagram vs tracing

diagram

noun
  • A graph or chart. 

  • A plan, drawing, sketch or outline to show how something works, or show the relationships between the parts of a whole. 

  • A functor from an index category to another category. The objects and morphisms of the index category need not have any internal substance, but rather merely outline the connective structure of at least some part of the diagram's codomain. If the index category is J and the codomain is C, then the diagram is said to be "of type J in C". 

  • Electrical diagrams show device interconnections. 

verb
  • To schedule the operations of a locomotive or train according to a diagram. 

  • To represent or indicate something using a diagram. 

tracing

noun
  • A record in the form of a graph made by a device such as a seismograph. 

  • The process of finding something that is lost by studying evidence. 

  • A regular path or track; a course. 

  • The reproduction of an image made by copying it through translucent paper. 

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