The structure of a song that outlines its repeating sections, harmonic structure, and introduction of new melodies or harmonies.
We’ll ignore the complicated history of form as applied to “classical” music and focus on song form as it is used in 20th and 21st century popular music.
A songwriter rarely starts off with note one and then composes entirely new melodies until he or she is finished. Most listeners would lose interest in such a song quickly. Popular music relies on the repetition of easy-to-remember melodies broken up by occasional contrasting segments of music. This balance of familiar and new gives a song its identity.
Perhaps the first truly American pop song form was the 12-bar Blues. This powerful combination – that uses only three chords – fueled rhythm and blues and early rock for decades. Recognizable examples include Little Richard’s “Tutti Frutti,” Elvis Presley’s “Hound Dog” and Big Joe Turner’s “Shake, Rattle and Roll.”
Early 1900s Broadway songwriters adapted a 32-bar format (4 sections, 8 measures each) from British “ballad operas” and used its variations for more than 50 years. They usually threw out a long, slow-tempo introductory section called the “verse” and focused on the section called the “chorus.” Those terms have different meanings today. Some 32-bar song forms include:
AABA: “I Got Rhythm,” “Satin Doll” (the 1960s hit “The Letter” is a rare rock and roll song in AABA form)
ABAC: “I Left My Heart in San Francisco” (again, performers other than Tony Bennett often ignore the introductory verse)
Folk Songs often follow an ABAB form. This emphasizes folk’s focus on simple, singable songs. Often the chords don’t change between sections, only the lyrics. Woody Guthrie’s “This Land Is Your Land” is a prime example. So is Bruce Springsteen’s “Born in the USA.”
By the 1960s songwriters had distilled popular music into three basic elements: a verse, a chorus, and a bridge (a contrasting segment of music). They perfected what is commonly called “Pop Song Form.” This formula was ideal for radio play and is still widely used today. The basic form is:
Verse (verse) Chorus; Verse (verse) Chorus; Bridge; (verse) Chorus repeating to fade (verses in parentheses are optional)
The Beatles became masters of pop song form and manipulated it at will, often opening songs with a chorus (“She Loves You,” “Help!”) to add excitement, and extending the form by repeating the bridge (“I Want to Hold Your Hand”) before the end. Even seemingly complex songs such as the Beach Boys’ “Good Vibrations” are variations of pop song form.
Rap music, although its musical foundation is often a sampled, repeated rhythmic and harmonic pattern, uses diverse verse/chorus combinations that creatively adapt pop song form. The wordplay in a rap is often rooted in a “call and response” style drawn from Gospel music and also incorporates African and African-American verbal games, known as “the dozens” and “signifying.”
Contemporary dance tracks often use a “step” form that begins with a simple foundation and then, at 8 or 16-bar junctions, adds a new element – a synth line, a vocal, percussion, etc. In this form the “breakbeat” – a section in which the rhythmic pattern either solos or stops entirely – often functions as a bridge, providing a transition between the top of the step and a return to the foundation.