(used with a sing. or pl. verb)1. A state of depression or melancholy. Often used with the.2. A style of music evolved from southern African-American secular songs and usually distinguished by a syncopated 4/4 rhythm, flatted thirds and sevenths, a 12-bar structure, and lyrics in a three-line stanza in which the second line repeats the first: The blues is an expression of anger against shame and humiliation (B.B. King, Essence November 1996).