Step 1: Understand the function of a multiplexer.
A multiplexer (MUX) is a device used to select one of several input signals and forward it to a single output line. It essentially combines multiple signals into one signal, which can then be transmitted or processed further. Step 2: Conclusion
Thus, the device that selects between several input signals and forwards the selected input is a multiplexer. Final Answer:
\[
\boxed{\text{Multiplexer}}
\]