Reverb

Short for reverberation. This is an effect device that mimics being in a room where you can hear the original sound reflect off the walls multiple times, bouncing around in a wash of sound until it eventually decays into silence. A reverb can greatly enhance the sound of a synthesizer, adding lushness and dimension to what might otherwise be a stark sound. There are relatively few modules that implement a reverb effect, and even fewer that allow you to voltage control some of its parameters (the ErbeVerb being the most famous); many just use an external reverb effect.