Complex jazz style developed in the 1940's. Also bop. A jazz style which developed in the 1940's characterized by very fast or very slow tempos with improvised lines of eighth notes, irregular accents, and an extended harmony. The patterns often ended with an abrupt two- note figure that sounded like " be-bop ".refers to the style of jazz pioneered by alto saxophonist Charlie Parker, trumpeter Dizzy Gillespie, pianist Thelonius Monk and others during the early 1940's. The word bebop is an onomatopoeia which describes quick staccato rhythms that often appeared in its melodies. "bebop" is sometimes called "bop" for short