distortion
An effect that clips the audio signal to produce a gritty, aggressive, harmonically rich guitar tone.
In Depth
Distortion occurs when an audio signal is pushed beyond the capacity of an amplifier or circuit, causing the waveform to clip. This adds harmonic overtones that create a thick, crunchy, or searing tone depending on the degree of clipping. Distortion is the defining sound of rock, metal, punk, and grunge guitar. Hard clipping produces aggressive distortion, while soft clipping yields the warmer sound called overdrive.
Link Wray is credited with inventing intentional distortion in 1958 by poking holes in his amplifier speaker cone with a pencil to record the song Rumble.