Clipping (audio)
What happens when a signal asks for more level than the format can hold: the peaks are sliced flat and the waveform turns into something it wasn't.
A fixed-point integer format has nothing above 0 dBFS. Any sample that should have been larger gets the largest legal value instead, and a sine wave with its tops cut off drifts towards a square wave — trailing a row of odd harmonics that the ear hears as rasp. Analogue stages clip more gently: transistors and valves bend the curve over gradually, which is why guitarists pay good money for it and recording engineers pay good money to avoid it.
Soft clipping has since become an effect in its own right, and mastering limiters use it on purpose. Inside a modern DAW everything runs in 32- or 64-bit floating point, so a channel can go far over zero without harm. The damage happens only when someone writes integers to disk, or when the D/A converter meets a peak hiding between the samples.