First time I've seen this question! Like hongtech sez, usually the confusion's the other way around!
Audio is like what's on a tape, or an LP, or a CD -- it's a recording of actual sound, transferred through some electromechanical/eletcronical magic into a stored form that can be played back again and again... Digital audio is a digital representation of sound waveforms, which is great because it can be so readily manipulated, sliced, diced, combined, copied, and so on...