A song is a piece of music for a single voice, typically with lyrics (words). It can be a cappella, or accompanied by instruments. Works for multiple voices may be called duets or trios, or larger ensembles are known as choral music. A song can be written by a songwriter or someone else, or it can be an existing folk or traditional song. Musicians can also create parodies of songs, or satirize them by changing the lyrics but keeping the melody and rhythm.
From the beginnings of recorded music, there have been many different styles of songs and their structures, which vary widely among cultures. Speech and music have been combined since earliest times, with the music heightening the emotion or meaning of the words. In some cultures, song has been an important medium for conveying religious or political ideas.
In the 17th century, there was a movement toward more sophisticated accompaniments for solo vocal songs. Art songs, such as the romantic love songs to an idealized or imaginary person that were first documented by the troubadours and bards of Europe, used flowing accompaniments to underpin, embellish, illustrate, or contrast with the singing voice. A separate genre developed, the aria, which was more musically elaborate and focused on the sung word while reducing the role of the supporting accompaniment.
Today, there is a wide variety of songs in different musical genres, including rock and pop songs, country music, jazz, and Broadway show tunes. These songs are usually characterized by melodies, lyrics, and grooves that have a strong connection to popular culture.