1. Specifically, an output device that produces graphic or pictorial representations of computer data on a hard copy by drawing with one or more automatically controlled pens that move in small steps as used with digital computers.
2. An automatic device used in conjunction with a digital computer to produce a graphic or pictorial representation of computer data on a hard copy.
3. A graphics printer that draws images with ink pens.

It draws point-to-point lines directly from vector graphics files.

The plotter was the first computer output device that could print graphics as well as accommodate full-size engineering and architectural drawings.