A memory area in a synth or soft synth that holds (usually) single-cycle samples of one or more waveforms. The wave data is arranged so that each waveform sample begins and ends at a zero-crossing point, so that a microprocessor can repeatedly output the data to produce a continuous wave output without clicks or pops. Doing so, it is possible to construct the digital equivalent of a voltage controlled oscillator, which offers many more choices of timbres than traditional analog VCOs. Wavetable-based synthesis became popular in the mid-1980s, when microprocessors became capable of performing the wavetable reading and output, but computer memory was still too expensive to store longer samples; wavetables provided some of the benefits of sample playback while using less memory.
Wavetables are also used for a method of synthesis called wave scanning, which is related to granular synthesis.