French diagramme, or Latin diagramma, Greek διάγραμμα that which is marked out by lines, a geometrical figure, written list, register, the gamut or scale in music, διαγράϕειν to mark out by lines, draw, draw out, write in a register, δια- through + γράϕειν to write.
- 1: a graphic design that explains rather than represents; especially : a drawing that shows arrangement and relations (as of parts)
- 2: a line drawing made for mathematical or scientific purposes
A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface. The word graph is sometimes used as a synonym for diagram.
Today, most diagrams are generated using diagramming software.