English: When two wall switches control the same light fixture, they are called "3-way" switches, because instead of one input and one output, they have 3 terminals (or wires, in the case of most dimmer switches). The two switches are connected together by a 3-wire (plus ground) cable, as depicted here. The hot wire is routed through both switches and back to the fixture via the white wire, which is marked with black paint at both ends. Disclaimer: This diagram is not a substitute for an instruction manual or professional installation. It is partial information, meant only to be educational.