Of or relating to European music during the latter half of the 18th and the early 19th centuries.
Of or relating to music in the educated European tradition

serious music

Yet Another example of meaning shift. I am continually surprised at how we all* take take so much pride of ownership in what are, in the final dusk of day, only received definitions (or as mav characterized it so finely, personal "positioning").
-ron obvious

*me too!

surprised enough, obviously, to do a double-take.