A song is a musical composition with lyrics (words) written specifically for music, often set to a pre-existing poem. The combination of the melody and words is protected by copyright, which allows the composer and lyricist to control who uses their work and how.
A song can be sung solo, with an instrumental accompaniment, or in a group. It may also be composed for more than one voice in a choral setting, such as an opera or oratorio.
Songs differ from poems in that the melody is not intended to be sung on the same pitch, but rather to create a specific emotion through the use of music. The lyric is also not meant to be sung on the same pitch, although it can be included in the same context to express an emotion.
The simplest form of song is a strophic song, in which the melody repeats or rises and falls in a series of notes. This strophic structure was a defining feature of European classical music until the late 18th century, when the Romantic song writers learned to vary a strophic melody with accompaniment and to utilize harmonies to enhance or illustrate their lyrics.
In some cases, the strophic pattern is used to tell a story, with each verse telling a different part of the tale. This can create a strong tension in the lyrics and help to keep the listener interested throughout the song.
The chorus is a chance to wrap up the big ideas in the song and to release any remaining tension. It’s a place to repeat the same lyrics as the verses and pre-chorus, and also to introduce a new or different lyric or to subvert the meaning of the song. It’s a good idea to include some variation in the chorus, especially if it uses a different chord progression from either the verse or pre-chorus.