The Collaborative International Dictionary of English v.0.48:
Switch \Switch\, n. [Cf. OD. swick a scourage, a whip. Cf.
1. A small, flexible twig or rod.
Mauritania, on the fifth medal, leads a horse with
something like a thread; in her other hand she holds
a switch. --Addison.
2. (Railways) A movable part of a rail; or of opposite rails,
for transferring cars from one track to another.
3. A separate mass or trees of hair, or of some substance (at
jute) made to resemble hair, worn on the head by women.
4. (Elec.) A device for shifting an electric current to
another circuit, or for making and breaking a circuit.
[Webster 1913 Suppl.]
Safety switch (Railways), a form of switch contrived to
prevent or lessen the danger of derailment of trains.
Switch back (Railways), an arrangement of tracks whereby
elevations otherwise insurmountable are passed. The track
ascends by a series of zigzags, the engine running
alternately forward and back, until the summit is reached.
Switch board (Elec.), a collection of switches in one piece
of apparatus, so arranged that a number of circuits may be
connected or combined in any desired manner.
Switch grass. (Bot.) See under Grass.