A piece of music designed to be played as an introduction, e.g., to a liturgical ceremony or, more usually, to another composition, such as a fugue or suite.  This connotation, which prevails throughout the entire early history of the prelude, was lost in the 19th century, when Chopin, Scriabin, and Debussy used the word as one of numerous noncommittal titles for piano pieces.  With few exceptions, the prelude has always been restricted to instrumental solo music, that is, to keyboard instruments and the lute.