Abstract In the beginning, the word jazz was not a noun naming a musical genre but probably an adjective describing a certain quality of movement and behavior: spirited, improvised, often sensual, and with a quirky rhythm. By the end of the second decade of this century the term was applied to both a kind of music and a kind of dancing. In the supplements to the Oxford English Dictionary (in the 1970s, when jazz and other slang terms were first admitted), the first definition of jazz is “a kind of ragtime dance.” Jazz dance and music are so intertwined that the origins and early history of each would be unthinkable without the other. How did they evolve together, foster each other, and even depend on each other for several decades? Why did the music and the dance eventually go separate ways? What are the long-range effects and implications of these developments? Jazz dance referred initially to several mostly syncopated popular dances, influenced by African-American traditions, which had originated in the southern United States.