1. To wind into continuous, regularly spaced rings one above the other; such as, to coil a wire around a pencil.
2. To wind on a flat surface into rings one around the other; such as, coiling a rope on the floor.
3. To gather rope, wire, string, etc. into loops.
4. To form rings, spirals, etc.
5. To gather or to retract in a circular way; such as, the snake coiled and struck out at the cat.
6. To move in or to follow a winding course; for example, the river could be seen from the cliff as it coiled through the valley.
7. A connected series of spirals or rings into which a rope or the such is wound.
8. An arrangement of pipes, coiled or in a series, as in a radiator.
9. In philately, a stamp issued in a roll, usually of 500 stamps, and usually perforated vertically or horizontally only or a coil of such stamps.
10. Etymology: Middle French coillir, "to collect"; from Latin colligere, "to gather", "to collect".

An iron-core coil whose inductance can be altered: An electrically variable coil can be modified over a wide range by changing a small DC control current.