1. A synthesizer sound which is stored in it's computer memory. Usually refers to a sound which can be altered, i.e. it's stored in RAM memory. Sometimes also called preset, program, or sound. Comes from the use of patch cords on the original modular synthesizers.

2. Verb: To connect together, as the inputs and outputs of various modules, generally with patch cords.

3. Noun: The configuration of hookups and settings that results from the process of patching, and, by extension, the sound that such a configuration creates. Often used to denote a single tone color or the contents of a memory location that contains parameter settings for such a tone color, even on an instrument that requires no physical patching.