Device

A device can be taken to mean:

Electrical device designed to carry power, but not use it
Instrument
Small appliance such as a TV set
Machine or functional part of a machine
Component of a computer or similar electronic system such as an integrated circuit, printer or network card
Device file or special file, an interface for a device driver that appears in a file system as if it were an ordinary file
Information appliance such as a cell phone or PDA
a part of a coat of arms
member of the pop band devices
an idea or invention
the word device is known as a primary word, meaning that it is so basic it is hard to define; this explains the multitude of definitions and examples for the word device.