From CCRMA Wiki
Open Sound Control (OSC)
Open Sound Control in a protocol developed at CNMAT for controlling sound synthesis applications. It can be used simply as a replacement for midi with meaningful message names that are easy to parse out in Max/MSP or Pd. It can also be used to create a heirarchy of message that are bound for different receivers and provides support for discovering the messages an application knows how to respond to.
Open Sound Control Specification