Peripheral

From Styleguide

peripheral

A joystick, racing wheel, hard drive or other optional hardware add-on intended for use with a videogame or computer system. Note that this definition does not encompass mandatory system components, such as a computer keyboard or the controller packaged with a system.

In certain highly specific cases, a peripheral also functions as a system unto itself. For example, the Sega CD and 32X function in this way. See the System Names appendix.

Capitalize the names of specific peripherals.

Example: Peripherals such as the Power Pad and the Power Glove were big sellers during the NES era.

Wrong: accessory, Peripheral, peripheral hardware.

Also see: controller, hardware.