Glossary of Terms:
 
bus
1) In audio, a circuit on a mixing board which routes an input signal to a desired output, section, or recorder track. Often used to assign multiple inputs to a single recorder track.
2) The act of routing incoming audio signals on a mixer to a desired output, section, or recorder track.
3) In computers, a common path between multiple devices.
Source: Yamaha

Also refered as:
  routing   stereo bus
Related terms:
  Firewire   USB   parallel bus   serial bus