Real Dictionary

jug band in American English
a kind of small string band or jazz band using simple instruments, as guitars, harmonicas, and kazoos, and makeshift ones, as washtubs or empty jugs
noun: a small group of performers who play chiefly blues or folk music on makeshift or very simple instruments, as washboards, harmonicas, kazoos, and empty jugs, the latter being played by blowing across the openings

jug band in British English
noun: a small group playing folk or jazz music, using empty jugs that are played by blowing across their openings to produce bass notes