Music Theory Resources

Basic form structures

Strophic A
Binary A-B
Ternary A-B-A
Rondo A-B-A-C-A
Sonata-Rondo A-B-A-C-A-B-A

Principles of Form

Form is the large-scale organization or shape of a piece of music. Formal structure helps listeners to perceive a piece as logical or coherent. Form is shaped by repeating material, varying familiar material, and introducing contrasting material.


When we describe a piece as 'catchy', we are really saying that it is easy to remember. Repetition is what allows sections of music to become familiar and fixed in our memories in that way. Repetition is also used in long pieces to maintain a sense of coherence and unity.

Although any element of music can be repeated (a note, a rhythm, a harmony, etc.), formal repetition refers to the recurrence of entire sections. In notation, these repeats are often indicated by a double barline and two dots. These are called repeat signs. Repeat signs often appear with first and second endings, which provide alternate measures of music for the first and second time a section is played.

Notation Name Meaning
backward repeat sign Backward repeat sign At the end of this measure, go back to the beginning or to the nearest preceding forward repeat sign.
forward repeat sign Forward repeat sign Matches up with a backward repeat sign to denote the measures to be repeated. When you reach a backward repeat sign, go back to the forward repeat sign and play all the measures between the two signs a second time.
first ending First ending The measures underneath the bracket should be played on the first time through a section, but should be skipped on the second pass.
second ending Second ending On the second time through a section, when the first ending is skipped, these measures should be played instead. Second endings will always follow first endings with repeat signs (see above).

There are also several other words and symbols that are used to indicate the order in which sections should be played and repeated. The chart below shows these symbols along with their names and meanings.

Notation Name Meaning
da capo Da capo Literally, 'from the head', this indication means to return to the beginning and play everything again.
fine Fine Literally, 'end', this symbol is used when the form of a piece is made complex by repetition, and the end of the piece falls at the end of an internal section rather than at the end of the notated measures. Fine is often used together with da capo (see below).
da capo al fine Da capo al fine Literally, 'from the head to the end', this is used when the composer wants the beginning of a piece to be repeated, but does not want the whole thing to be heard again. The performer should return to the beginning and play up until fine appears in the music (see above).
coda Coda From the Italian for 'tail', a coda is an extra section added at the end of a piece. Typically, the symbol to the left is used in the main body of the piece to indicate when the performer should jump from the main body to the coda. By convention, the performer never skips to the coda on the first time through a section, but only after a repeat has occurred. The coda itself is marked with either 'coda' or both the symbol and the word.
segno Segno Meaning 'sign' in Italian, the segno is used to mark where a repetition should begin. This is used only when the form is too complex for a forward repeat sign to be used.
dal segno al coda Dal segno al Coda Literally 'from the sign to the coda', this indicates that the player should go to the segno, play to the coda symbol, then go to the coda and play it as well.


In music, contrast is used to create variety and build drama and tension. By withholding familiar material and using contrasting music instead, the composer can create discomfort, longing, or disorientation in an audience. In longer pieces, repetition helps create cohesion, but alone it is not enough to hold the attention of an audience. Contrast is introduced into these pieces to maintain interest and spread out repetition. Drama can also be achieved through the use of contrasting material. Following a quiet section with a loud one, or a slow section with a fast one can surprise and disorient audiences, while following a lifeless section with a triumphant one can invigorate them.


Variation is essentially a combination of the principles of repetition and contrast. Variation occurs when a section returns, but is not identical to its previous iteration(s). Some aspects of the section remain the same so that it is (usually) recognizable, but others are changed to create variety. Thus variation allows for both the familiarity of repetition and the interest of contrast.

Formal Archetypes

All pieces with formal organization can be seen as expanded or modified versions of the basic paradigms below.

  • Strophic - one section repeats over and over again: AAA etc.
  • Binary - two contrasting sections: AB
    • sections may be repeated, resulting in AABB
  • Ternary - two contrasting sections, the first section returns: ABA
    • sections may be repeated, resulting in AABBAA or AABBA
    • this form is distinct from binary form because the A section returns after the B section
  • Rondo - one section returns over and over again (a refrain), alternating with contrasting sections
    • there are several different versions of rondo form (ABACA, ABACABA, etc.), but it is always defined by many returns of the A section separated by contrasting material
  • Theme and Variations - same material returns but is slightly or substantially varied from its original form: AA1A2A3 etc.
    • variations are indicated with superscript numbers

Add-Ons: Introduction and Coda

There are two optional sections that can be added onto any form: an introduction at the beginning, and a coda at the end. An introduction is designed to grab the attention of listeners and 'set the stage' for the body of the piece. A coda (from the Italian word for 'tail') is designed to bring a greater sense of closure to a piece than would be possible within the body of the form.

Adding an introduction and/or coda to a piece does not change its fundamental form - these sections are considered ancillary and simply provide a frame for the main substance of the piece.

Composite Forms

Sometimes a large work, like a symphony, consists of several distinct movements or smaller pieces that are related but distinct from each other. These large works are called composite forms. Each movement of a composite form may be ternary, binary, or any form, but it is seen as belonging to a larger meta-form. This is similar to the idea of a concept album in popular music. Each piece is distinct from the others, but the collection is conceived as a whole.

Examples of composite forms include symphonies (usually 4 movements), concertos (3 movements), song cycles (groups of several songs telling a story or sharing a theme), and suites (collections of stylized dance movements).

No Form

It is important to note that there are some pieces that do not fit into any of the forms discussed above. This occurs when pieces lack formal repetition and variation, and do not divide into two contrasting sections as in binary form. These pieces do not follow a fixed form, but are through-composed, meaning that the composer created new material for each section of the piece. Many examples of this can be found in Renaissance madrigals and Romantic art songs (Franz Schubert's Lieder, for example), but there are a few through-composed pieces in popular music as well. These include Queen's "Bohemian Rhapsody", The Beatles' "Happiness is a Warm Gun", and Radiohead's "Paranoid Android".

Form in Popular Music

Like all music, popular music relies on repetition, contrast, and variation. Repetition is especially critical in music that is designed to be memorable (like advertising jingles) or music that must be predictable (like dance music). Given the importance of repetition in popular music, it is no surprise that there are not many songs in the popular sphere that are through-composed (although a few examples were mentioned in Form Archetypes) or that follow a theme and variations form.

Popular music is dominated by songs with instrumental accompaniment. Over time, specialized terminology has developed to discuss song forms. Here are the important terms:

  • Verse – same music, different lyrics
  • Chorus (Refrain) – same music, same words
  • Bridge – contrasting material that connects two sections (usually falls between choruses)
  • Break – instrumental interlude
  • Introduction (Intro) - opening material
  • Coda (Outro) - closing material

Verse-Chorus Form

Verse-chorus form is often used in classic rock of the '60s and '70s, but appears in a variety of popular sub-genres. Examples include "Get Back" by the Beatles (1969), "Proud Mary" by Creedence Clearwater Revival (1969), and the "Hotel California" by the Eagles (1977). In this form, verses simply alternate with choruses for as many repetitions as the composer (songwriter) chooses. Thus, it is actually a variation of strophic form.

A A A ...
Verse Chorus Verse Chorus Verse Chorus ...

32-bar Form

32-bar form was particularly popular in the American songs of Tin Pan Alley and movie musicals of the '30s and '40s. "Somewhere Over the Rainbow" from The Wizard of Oz (1939) is an example of this form. 32-bar form gets its name because each of the four sections typically contains 8 bars (measures), making a total of 32 bars for the whole song. There is no chorus in this form. Instead, there is a verse that is repeated (with different lyrics), which is followed by a contrasting bridge, and the piece is concluded with a final verse. This form is a variation on the ternary archetype.

Verse Verse Bridge Verse

Verse-Chorus Form with Bridge

Combining verse-chorus form and 32-bar form results in verse-chorus form with a bridge. This is the most common form in modern popular music. Examples include "I'll Follow You Into the Dark" by Death Cab for Cutie (2005) and "Poker Face" by Lady GaGa (2008). The final A section may have both a verse and chorus, but usually consists of only the chorus, which may be repeated several times.

A A B A 1
Verse Chorus Verse Chorus Bridge Verse (often omitted) Chorus (often repeated)

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