MIDI patch - technical definition

One of 16 channels in a MIDI device. Many keyboard synthesizers and MIDI sound modules can handle several waveforms per patch, mixing different instruments together to create synthetic sounds. Each waveform counts as a MIDI voice. Some sound cards can support two or more waveforms per patch.

Before General MIDI, which standardized patches, MIDI vendors assigned patch numbers to their synthesizer products in an arbitrary manner. See MIDI voices.