Mainstream jazz

Mainstream jazz is a genre of jazz music that was first used in reference to the playing styles around the 1950s of musicians like Buck Clayton among others; performers who once heralded from the era of big band swing music whom did not abandon swing for bebop, instead performing the music in smaller ensembles. The medium once lay dormant during the 1960s, but regained popularity in the 70s.

Source : http://en.wikipedia.org/wiki/Mainstream_jazz