It is said that the expression -'Jazz'- arose during the late nineteenth century in the better brothels of New Orleans, which provided music and dancing as well as sex. The original jazz band, according to Herbert Asbury's 'The Latin Quarter' (1938), was the 'Spasm (sic) Band', made up of seven boys, aged twelve to fifteen, who first appeared in New Orleans about 1895. They advertised themselves as the "Razzy Dazzy Spasm Band." When, about 1900, another band adopted the same billing for an appearance at the Haymarket dance hall, the 'Spasms' loaded their pockets with rocks and dropped by to protest the infringement. This prompted the owner of the hall to repaint his advertising placards to read: "Razzy Dazzy Jazzy Band!" If the memories of Asbury's sources were correct--and he talked to two surviving members of the 'Spasms' --this represents the word's earliest-known appearance in print.

Jazz is not a bad word now, but almost certainly is of extremely low origin, referring to copulation before it was applied to music, dancing, and nonsense (i.e., "all that jazz"). "If the truth were known about the origin of 'Jazz' it would never be mentioned in polite society . . .The vulgar word 'Jazz' was in general currency in dance halls thirty years or more ago" (Clay Smith, "Etude," 9/24). "According to Raven I. McDavid, Sr., of Greenville, S.C., the announcement, in 1919, of the first 'Jazz band' to play in Columbia, where he was then serving in the state legislature, inspired feelings of terror among the local Baptists such as what might have been aroused by a personal appearance of Yahweh. Until that time 'jazz' had never been heard in the Palmetto States except as a verb meaning to copulate" (H. L. Mencken, 'The American Language,' Raven I. McDavid, Jr., 1963). "'She never stepped out of line once in all the years we been teamed up. I can't sell her on jazzing the chump now'" (William Lindsay Gresham, 'Nightmare Alley,' 1946).

'Jazz' probably comes from a Creole or perhaps African word, but exact connections have not been proven. What ever, the presumed sexual origin is quite in accord with the development of many other related words, most notably:

'boogie-woogie'
--Used in the nineteenth century by blacks in the American South to refer to secondary syphilis.

'gig'
--The musician's engagement probably derives immediately from the 'gig' that is a dance or party, but 'gig' and 'gigi' (or 'giggy') also are old slang terms for the vulva; the first has been dated to the seventeenth century.

'jelly roll'
--Black slang from the nineteenth century for the vulva, with various related meanings, i.e. sexual intercourse, a loving woman, a man obsessed with finding same. "'What yo' want?' she asked softly. 'Jelly roll?'" (Thomas Wolfe, 'Look Homeward Angel,' 1929). The term probably derives from 'jelly,' meaning semen: "Give her cold jelly to take up her belly, And once a day swinge her again" (John Fletcher, 'The Beggar's Bush,' 1622). Related expressions include 'jelly bag,' referring both to the scrotum and the female genitals; 'jerk [one's] jelly,' to masturbate; and 'jelly,' a good-looking woman. 'Jelly Roll' appears in many blues songs, such as "I Ain't Gonna Give Nobody None o' My Jelly Roll," "Nobody in Town Can Bake a Jelly Roll Like Mine," and "Jelly Roll Blues," the last by Ferdinand Joseph La Menthe "Jelly Roll" Morton (1885-1941).

'juke'
--The modern 'jukebox' was preceded by a 'Juke house,' which was a brothel to Southern blacks, the basic term coming from a Gullah word meaning disorderly or wicked.

'Swing'
--The now archaic 'swinge" was used for many years as a synonym for copulation ("=swive," according to the OED's discreet definition). Note the quote from 1622 in 'jelly roll' above. Or as John Dryden put it: "And that baggage, Beatrix, how I would swinge her if I could" ('Enemy's Love,' 1668). The oldest meaning of both 'swinge' and 'swing' deal with beating, striking, and whipping (i.e., the swing of a weapon predates the back and forth swaying of a swing or the rhythmic swing of music). For reasons that are not hard to guess, the conjunction of violent and sexual senses within the same word is very common
In a more modern sense, Swing has been used describing 'wife-swapping' and related activities involving one or more partners of either sex. It has been so used from about 1964 on, -or earlier, depending on the interpretation one gives to Frank Sinatra's 1956 record album 'Songs for Swinging Lovers").
This discourse (slightly modified) on Jazz Etymology was excerpted from 'Wicked Words', and was passed along to the BBDB by Mr. Raymundo Eli Rojas