shifter

noun

1. One who, or that which, shifts or changes.
2. A word whose meaning changes depending on the situation, as by deixis.
3. Someone who plays tricks; a trickster.
4. An assistant to the ship's cook in washing, soaking, and shifting the salt provisions.
5. A control device (usually a lever or button) for shifting gears in a gearbox, or an arrangement for shifting a belt sidewise from one pulley to another.
6. A wire for changing a loop from one needle to another, as in narrowing, etc.
7. A component used by the rider to control the gearing mechanisms and select the desired gear ratio, usually connected to the derailleur by a mechanical actuation cable.
8. A spanner with an adjustable jaw size.
9. A person employed to repair the horseways and other passages, and keep them unobstructed.
10. A switcher or shunter: a railroad locomotive used for shunting.
11. A shape-shifter; a person or other being capable of changing their physical form, especially a lycanthrope.
12. A shiftworker.