I make references to The Jazz Tradition frequently, so here is a handy definition for you.
The Jazz Tradition is a reduction of a basic jazz canon which most musicians, critics, and listeners can agree upon. The Jazz Tradition is by nature restrictive and exclusive, since most jazz enthusiasts have a hard time agreeing on who should and should not be included in the pantheon of essential jazz musicians, beyond the obvious examples like Thelonious Monk or Coleman Hawkins. The Jazz Tradition is always capitalized. The Jazz Tradition is both useful and limiting, as it creates a reference point for what has historically come to be known as jazz but belies the complexity, depth, and breadth of the music.
The Jazz Tradition is an anachronistic term used in a historical sense to describe the landmarks of jazz that shaped the music until the present day. If a musician is a significant stylistic and cultural influence in jazz history, then he or she is part of The Jazz Tradition. Charlie Parker and Clifford Brown are part of The Jazz Tradition, but Muhal Richard Abrams and John McLaughlin are not part of The Jazz Tradition. All four play jazz, but only the first two fit within the confines of The Jazz Tradition.
Mythology plays an important role in The Jazz Tradition. The Jazz Tradition features many types of martyrs; the saintly Clifford Brown, the tragic Charlie Parker, the enlightened John Coltrane. Then there are the creation myths: Louis Armstrong's rites of passage in Storyville, jam sessions at Minton's, Ornette Coleman's debut at The Five Spot. The Jazz Tradition is not merely a canon, but a historical narrative with characters and scenes as colorful as those found in a Steinbeck novel.
But The Jazz Tradition is also an ephemeral idea, so don't spend too much time trying to define it; you will only end up going in circles.