American form of folk music related to jazz. It is based on a simple, repetitive, poetic-musical structure. in a jazz context, when "blues" or "solo on blues" appears at the start of a solo section, it is an abbreviation for "blues progression"; it instructs the performer to improvise solos over a 12-bar blues progression based on I, IV, and V7 chords.a type of slow, melancholy, rhythmic song, which originated in black folk music. Classical composers such as Ravel and Gershwin were influenced by blues, which is still popular today