Bop and Bebop and synonymous.  Both were used (initially by the press, later by the musicians themselves) to refer to the jazz style popularized by Charlie Parker, Dizzy Gillespie, Thelonious Monk, Bud Powell, et al. in the early 1940's.  The term was derived from syllables typically used in scat singing (vocalizations with asensical syllabels instead of words). 
  Matt 10/8/05