Definition - American music developed especially from ragtime and blues and characterized by propulsive syncopated rhythms, polyphonic ensemble playing, varying degrees of improvisation, and often deliberate distortions of pitch and timbre.
There are many conflicting and confusing stories about the origins of the word jazz. Few, if any reference works on language are ready to make any definite pronouncements as to its etymology. The Oxford English Dictionary has written evidence for two distinct senses of the noun (meaning "energy" and "rubbish") before it was used to refer to a type of music.
However, the earliest written use for all three of these senses of the noun occurs within a three year span; this, coupled with the fact that jazz would have certainly been in spoken use for some time prior to this (there are other senses of the word, such as "to copulate with," which would have been considered vulgar, and unlikely to have been printed), means that we really don't know which sense of the word was the first to arrive in English.
And the chorus. They must have put the "J" to "Jazz," for they teemed with pepper and ginger.
— The Winnipeg Tribune (Winnipeg, Can.), 28 Jun. 1913