A multiplexer, often abbreviated as MUX, is an electronic device that selects one of several input signals and forwards the chosen input to a single output line. It acts like a digital switch, allowing multiple data sources to share a single communication channel. This is particularly useful in reducing the number of wires needed in a circuit. Multiplexers are commonly used in various applications, including telecommunications, data routing, and signal processing. They can be controlled by a set of selection lines, which determine which input is connected to the output. This functionality makes multiplexers essential in modern electronic systems.