Dating back to 1860 there had been an African-American slang term, ‘jasm’, which means ‘vim’ or ‘energy’.
‘Jazz’ was named the Word of the 20th Century by the American Dialect Society, which is remarkable since we don’t actually know for sure from where the term originates. One of the most striking features of jazz to its earliest listeners was its speed, its sheer energy. Dating back to 1860 there had been an African-American slang term, ‘jasm’, which means ‘vim’ or ‘energy’.  On 14 November 1916, the New Orleans Times-Picayune newspaper referred for the first time to “jas bands”.  That particular spelling suggests “jas” could have come from jasm. Or perhaps it referred to the jasmine perfume that prostitutes in New Orleans’ famed Storyville red light district often wore – jazz music had developed, in part, as the music played in brothels. Early jazz pioneer Jelly Roll Morton, whose own name was a euphemism for sex, first developed his own style playing piano in these ‘sporting houses’ and to get extra tips he’d peek at a prostitute and her client through a peephole and time his playing with the pace of their revels.