What does 'Pure Music' mean?

There are five volumes of Nancarrow Player Piano music. That's two steam driven synchronised pianolas playing as many notes as mechanically possible a lot of the time. Lot's of piano strings were broken when Wergo made these recordings at Nancarrow's Mexico City home not long before his death, so the five volumes are like his complete contribution to music for steam driven synchronised pianolas.

They have to be heard -- they are funny/witty, but also strikingly rich in 'content' -- there are no superfluous flurries of faked virtuosity. Perhaps that's what was meant by 'pure music', but when I think of this stuff I have to admit that the boogie-woogie initiated pieces are more bent than Liberace could ever possibly have achieved - - this is not music unaware of the limitations and compromises of other music, which makes it funny and some would say satirical, not 'pure', imho.

A library near you _should_ have it.

I would use this term to describe music for music's sake. For example, a classical "Air" might be "pure music" because it's not about anything in particular, and wasn't written for the church or a theatrical work.