A song is a musical composition in which the lyrics and melody are combined with one or more instruments. It is also a piece of music that is performed by a vocalist, either as a solo performance or with other singers (such as a duo, trio, quartet, or larger group).
The structure of a song can vary widely, but it is most often structured in the form of an intro, verses, a chorus, and an outro. It may be a cyclical structure, such as the traditional folk song format, or it can follow a linear pattern such as the popular ABABCB structure, most commonly used in rock music.
Many songs are introduced by an instrumental intro, which sets the mood and introduces the main musical elements. Then the song begins with a vocal or instrumental verse, which typically has a melodic hook that focuses on specific words. The song then moves into the chorus, which has a more repetitive melody and lyrical content than the verses. This is where most of the listener’s attention will be focused.
Most songs have a bridge section that contrasts with the rest of the song both lyrically and musically. For example, the bridge of a song might have a different chord progression than the verse and chorus or it might feature an instrumental solo. A typical bridge is brief and occurs only once, before the chorus re-enters to bring the song to a close.