Rapping (or rhyming, spitting, emceeing, MCing) is a musical form of vocal delivery that incorporates "rhyme, rhythmic speech, and street vernacular", which is performed or chanted in a variety of ways, usually over a backbeat or musical accompaniment. The components of rap include "content" (what is being said), "flow" (rhythm, rhyme), and "delivery" (cadence, tone). Rap differs from spoken-word poetry in that rap is usually performed in time to an instrumental track.