3 Way Switch Feed At Light. While standard single-pole switches have two screw terminals on one side of the switch, plus a third green grounding screw terminal connected to the metal strap, three-way switches have three screw terminals plus a ground. First, connect all ground wires as previously described.

All they do is turn a light on and off.
If the words On and Off A three-way switch has at least three wires, and possibly four, depending on whether it has a ground wire.
While standard single-pole switches have two screw terminals on one side of the switch, plus a third green grounding screw terminal connected to the metal strap, three-way switches have three screw terminals plus a ground. In a three-way switch, the top terminal connects to one or the other of the bottom two terminals. (Note: The actual terminal configuration on a three-way There are several other ways to wire three-way switches to a light. Three-way switches & light fixture with duplex receptacle.