Jazz is a musical form which started around the same time as the 20th century, it was the Black communities in the Southern United States that led the way in the genre of Jazz, with an influence from African and European music traditions.
From its earliest days until its later days, jazz has also made use of music inspiration from 19th and 20th century, it could be described as "American popular music, which is based on European music traditions".
The word jazz began as a West Coast slang term of uncertain derivation and was first used to refer to music in Chicago in about 1915.
Jazz has, from its formative years, spawned a variety of sub genres, this list would include;-
New Orleans Jazz and Dixieland Jazz dating from the early 1910s
Big Band-Style and Swing hailing from the 1930s and 1940s
Bebop, growing out of the mid-1940s
Latin-Jazz fusions such as Afro-Cuban and Brazilian Jazz dating from the 1950s and 1960s
Jazz Rock fusion from the 1970s
Acid Jazz, a much later development
Jazz will often mix with many other genres creating Jazz Fusion
The anarchistic attitude that can be found within Free Jazz