[quote name='Zenitram' timestamp='1390564886' post='2346870']
Why is recording an instrument sometimes called tracking?
[/quote]
Back in days of yore, a recording was usually made to magnetic tape, divided up into several tracks - typically 4, 8, 16, etc. Each track would hold a single instrument/voice, or possibly a sub-mix of several instruments. The tracks can all be recorded at once, or separately. So "tracking" is the act of recording one or more tracks onto the tape, as opposed to "mixing" which is setting the relative volumes of each track after they have been recorded. The name has carried over into the modern digital world.