Noun
hard bop (uncountable)
A subgenre of jazz music that extends bebop with influences from rhythm and blues, gospel music, and blues.
A few critics go as far as to call Walkin' the album that created hard bop, but the point is debatable, given the number of musicians who were working along similar lines at the same time (many of whom recorded or played with Davis). Source: Internet
Down Beat May 13. Jazz-rock Although some jazz purists protested against the blend of jazz and rock, many jazz innovators crossed over from the contemporary hard bop scene into fusion. Source: Internet
In contrast with bebop, hard bop used slower tempos and a less radical approach to harmony and melody, often adopting popular tunes and standards from the American songbook as starting points for improvisation. Source: Internet