A specific type of distortion. If a signal is passed through an electronic device which cannot accommodate its maximum voltage or current requirements, the waveform of the signal is sometimes said to be clipped, because it looks on a scope like its peaks have been clipped off by a pair of scissors. A clipped waveform contains a great deal of harmonic distortion (see WFTD archive harmonic distortion) and often sounds very rough and harsh. Clipping is what typically happens when an audio amplifier output is overloaded or its input over driven.
Interestingly, light to moderate clipping does not usually reduce the intelligibility of some signals, especially speech. In fact, it has been shown that clipped speech is easier to understand than normal speech in noisy environments. A probable reason for this is the increased high frequency content that accompanies this type of distortion, which can make a signal stand out more among other sounds and noises. Aphex and some other companies have been using this principle for years in their “exciter” type products. By adding the right amount of distortion at the right frequencies a signal will sound almost clearer and more distinct amidst other sounds, thus standing out more in a mix.