What are other terms commonly used for a peripheral device?

The term "peripheral device" refers specifically to hardware that is not part of the central processing unit (CPU) and is used to add functionality to a system. The correct choice includes "peripheral," which is the primary term itself, and also encompasses "I/O device" and "input-output device," both of which describe devices that facilitate interaction between the user and the computer. These devices can handle both input (like keyboards and mice) and output (like monitors and printers), making them essential for a complete user experience.

In contrast, while "accessory hardware" might refer to secondary devices, it is not as commonly accepted as a synonym for peripheral. "Network interface" specifically identifies devices that manage network connections, which is a narrower classification. "System component" is a broader term that may cover internal parts of a computer system, such as the motherboard or CPU, but does not specifically apply to external devices. Since the correct answer embraces the most widely recognized terms associated with peripheral devices, it accurately captures the essence of the concept.