diagram vs plan

diagram

noun
  • 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. 

  • A graph or chart. 

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

  • To represent or indicate something using a diagram. 

plan

noun
  • A drawing showing technical details of a building, machine, etc., with unwanted details omitted, and often using symbols rather than detailed drawing to represent doors, valves, etc. 

  • A subscription to a service. 

  • A set of intended actions, usually mutually related, through which one expects to achieve a goal. 

  • A method; a way of procedure; a custom. 

  • A two-dimensional drawing of a building as seen from above with obscuring or irrelevant details such as roof removed, or of a floor of a building, revealing the internal layout; as distinct from the elevation. 

verb
  • To create a plan for. 

  • To intend. 

  • To design (a building, machine, etc.). 

  • To make a plan. 

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