Advanced Audio Distribution Profile (A2DP)
This profile defines how high quality audio (stereo or mono) can be streamed from one device to another over a Bluetooth connection. For example, music can be streamed from a mobile phone, to a wireless headset, hearing aid & cochlear implant streamer, or car audio or from a laptop/desktop to a wireless headset.
Source: Advanced Audio Distribution Profile section of "List of Bluetooth profiles" article on Wikipedia