A coil may refer to any of the following:
Short for electromagnetic coil, a coil is conducting wire such as copper shaped in a helical form around an iron core. The coil creates an inductor or electromagnet to store magnetic energy. Coils are often used to remove power spikes and dips from power. The picture is an example of an inductor on a computer motherboard.
A coil can also refer to a spring.
The core of a coil is usually iron, however, it may also be plastic or air.
Computer abbreviations, Electromagnet, Electronics terms, Power terms, Transformer