toggle switch

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A switch that uses a toggle joint with a spring to open or close an electric circuit as an attached lever is pushed through a small arc.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Elec.) an electrical switch operated by pushing a lever through a small angle of deflection. The lever has a spring which returns it to its original position after the pressure applied by the operator is released.
• noun (Computer programming) A mechanism for acquiring input from an operator, such that taking some action (such as pressing a function key on a keyboard) will cause a program variable to take a new value. The values are usually changed in cyclic fashion, so that a certain number of activations of the toggle returns the variable to its initial value. When there are two values to the variable, each activation of the toggle causes the variable to assume the alternate value.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A switch, usually with two positions, actuated by moving a small lever.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a hinged switch that can assume either of two positions