A controller which moves in two dimensions and usually produces two control voltages, or equivalent signals, one corresponding to each axis of movement of the joystick. Joystick controllers used with synths are usually smaller affairs with a plain cylindrical shaft, unlike those used with video games which often feature large handgrips and triggers. A synth joystick may or may not be sprung so that it returns to the center when released. It may have a pushbutton at the end of the stick, which can generate gate or trigger signals when pressed.
Joysticks in synths do not have a standardized use. Many Korg synths of the 1980s used a joystick as a substitute for conventional pitch and mod wheels; moving the stick left and right caused pitch bend, where moving it back and forth sent a modulation signal from a LFO to various destinations. Synths that implement vector synthesis often use a joystick as the source of the vector. Modular synths sometimes have a joystick controller that can generate control voltages which can be routed to various destinations.