What is Jazz?

In the words of C of C's Composer in Residence, David W. Maves:

Jazz is improvisation over changes. What that means is that there is an agreed upon set of chords (ofttimes only 3, the I chord the IV chord and the V chord = a typical blues progression, many jazz favorites, and every Stephen Foster song).

The problem is that that leaves out most of Duke Ellington's music, a surprising amount of which is/was written out quite precisely. That and the music of Gershwin, for example, are exceptions.

So, short answer for amateurs: Jazz is what happens when jazz players improvise using an agreed upon series of chords (or chord progression) (over and over). (They often have a common melody in mind when they do this, sometimes playing or singing the melody in a recognizable form, especially at the beginning of an improvisation, but it is the chord progression that keeps the performers united throughout the work.) So it is series of improvised variations.

Visit David Maves' web site at http://www.cofc.edu/~mavesweb.