Does anyone have a succinct way of defining "Western Music" as opposed to "Non-Western Music"?
My own definition of "Western" music is a bit complicated and not necessarily entirely correct. Western Music is the music which is oriented towards harmonic expression being approximately as important as melodic and rhythmic expression, including this music's direct precursors and successors. The definition is intentionally vague as the boundaries of what is "Western" and "non-Western" is not sharp. Each genre may borrow techniques from the others.
Succinct term is "12EDO". It means twelve Equal Divisions of the Octave. This term is used in the microtonal world to identify twelve note equal temperament, which is/was the predominant tuning and harmonic system during the 20th century, and still predominates today (unfortunately;-).