plotter -
an instrument (usually driven by a computer) for drawing graphs or pictures
instrument the means whereby some act is accomplished; "my greed was the instrument of my destruction"; "science has given us new tools to fight disease"
plotter -
An output device that draws graphs and other pictorial images on paper, sometimes using attached pens.
Wikipedia
A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers, and it is now commonplace to refer to such wide-format printers as "plotters," even though they technically aren't.