Webster's Revised Unabridged Dictionary · 1913

A suffix signifying something written (as in digraph), a writing; also, a writer or an instrument that produces a written or visible record of a measurement, such as a spectrograph; as, autograph, crystograph, telegraph, photograph.

(Mathematics) A curve or surface, the locus of a point whose coordinates are the variables in the equation of the locus; as, a graph of the exponential function.

A diagram symbolizing a system of interrelations of variable quantities using points represented by spots, or by lines to represent the relations of continuous variables. More than one set of interrelations may be presented on one graph, in which case the spots or lines are typically distinguishable from each other, as by color, shape, thickness, continuity, etc. A diagram in which relationships between variables are represented by other visual means is sometimes called a graph, as in a bar graph, but may also be called a chart.