Jazz dance is an umbrella term encompassing several different styles of dance that became popular in the early 20th-century. Though jazz dance has mixed roots extending back through both African and European traditions, it's a uniquely American creation, which developed simultaneously with jazz music in New Orleans.
Eventually, this kind of social song and dance became popularized beyond the African American communities, especially as Southern blacks migrated to Northern cities during the Great Migration.
Social dances like the Charleston and the Jitterbug caught on. In the 1940s, the improvised, social aspect of jazz dance began to be replaced with intricate choreography as more dancers with training in ballet and Modern took up the dance form, especially on Broadway stages.
Today, jazz dance continues to evolve and blend with other dance styles — for example, street jazz and theatre dance. However, true to its roots, jazz dance continues to hearken back to the ethnic eclecticism that birthed it.