A series of connected spirals or concentric rings formed by gathering or winding: Various devices that have spirals that are the major components can be termed as coils, like an inductor coil.

An electrical conductor twined into the form of a spiral: Coils can be electric devices consisting of one or more turns of wires which asre used to introduce inductance into electric currents or the properties of electric circuits as a result of which electromotive forces are created by changes of currents.