These terms are extremely common among electricians, but if you don’t often work with wiring, it can be a bit confusing. Let’s clear it up.; A one-way switch is the simplest switch. When it’s on, the two terminals are connected, and when it’s off, they’re not. Several of the light switches in your house are likely one-way because it just means the light can be switched on and off only from that particular switch. A two-way switch is basically two one-way switches combined, which allows you to control a single device from two locations. A common example would be a large room or long hallway with two switches for the same light.; Three-way and four-way switches simply add more connectivity, allowing you to control lights and other devices from multiple locations throughout your home.; Smart light switches are generally one- or two-way, but there are examples of three- and four-way, too. Sometimes, they interface with a separate wireless receiver, which can broadcast a signal across your home for multi-way connections.;