The most commonly available and used electrical switches in our homes is the one-way switch. But there also exists two-way switch, though not commonly used. In its working, the main difference between them is the number of contacts they each have. The one-way switch has two contacts and the two-way switch has three contacts. In a two-way switch, there are two, one-way switches combined in one. One of the terminals can be connected to either of the two, but not both at the same time.
The advantage of a two-way switch is the ability to control a single device from two separate locations.