A Device is a unit of physical hardware or equipment that provides one or more computing functions within a computer system. It can provide input to the computer, accept output, or both. A device can be any electronic element with some computing ability that supports the installation of firmware or third-party software. Typical hardware includes a computer mouse, speakers, printer, and microphone. A device may also be referred to as an appliance, gadget or electronic tool.
When the term is used generally (as in computer devices ), it can include keyboards, mouses, display monitors, hard disk drives, CD-ROM players, printers, audio speakers and microphones, and other hardware units. Some devices such as a hard disk drive or a CD-ROM drive, while physically inside the computer housing, are considered devices because they are separately installable and replaceable. With notebooks and smaller computers, devices tend to be more physically integrated with the "non-device" part of the computer.
The units of a computer to which the terminal device is not applied include the motherboard, the main processor, and additional processors such as numeric coprocessors, and random access memory (RAM).
The term peripheral (a truncation of the peripheral device) is sometimes used as a synonym for a device or any input/output unit.