In electronic music, usually refers to a circuit that performs the type of wave shaping known as clipping. The intent of a distortion circuit is to produce a "dirty" sound similar to that of a heavy-rock guitar sound, usually containing a high degree of even harmonics and a certain amount of intermodulation. Many recent synth designs offer distortion as a built-in effect, and some modular manufacturers offer distortion modules in which the amount of distortion is voltage control. The characteristic sound of some filter circuits is produced by distortion that occurrs internally in the filter, examples being the Moog transistor ladder filter and the Roland TB-303 filter.
A synthesist might also produce distortion the same way that electric guitarists and others do, using stomp box effects intended for guitar. This can run into several problems, including the fact that synth signal voltage levels are considerably higher than the output of a passive electric guitar pickup, and that distortion that sounds good on a guitar signal may be unacceptably harsh when applied to a synth. However, in the mid-2010s, stomp box manufacturers have become conscious of the fact that synth players are using their devices, and they have began to incorporate features in the boxes specifically to be used with a synth, such as line-level inputs and outputs. (The Moogerfooger line of stomp box effects from Moog comes at this from the opposite direction, packaging synth circuits to be usable with both synth and guitar.)
The word "distortion" is also sometimes used by synthesists in the audiophile sense, as an unintended (and usually unpleasant) alteration of a signal, produced by circuit defects or excessive signal levels within the circuit.