MUS 211 Study Guide D (Chapter 4)

Binary and Ternary Forms

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Review of Smaller Forms

  1. Phrase--a group of notes, often four measures in length, leading to a cadence.  Phrases may be shorter, usually not less than three measures, or they may be longer, usually by extension.

  1. Period--consists of two phrases, called antecedent and consequent, the first usually ending with a half cadence, though any cadence (including a perfect authentic on occasion) is possible.  The second phrase normally ends with a perfect authentic cadence.
  1. Parallel Period--when the melodic line of each phrase is similar.
  1. Contrasting Period--when the melodic line of each phrase differs.
  1. Double Period--consists of two periods.  Only the last of the four phrases ends in a perfect authentic cadence.
  1. Phrase Group--a series of phrases, some of which may be unrelated or lacking closure, which do not arrange themselves conveniently into periods.

Binary and Ternary Forms Defined

  1. The terms binary and ternary refer to larger structures that may be divided into two or three parts, respectively, and include the following features:
  • Each part of a binary or ternary structure consists of one of the smaller forms: a phrase (uncommon), a period, a phrase group, or a double period.  Extensions of phrases are commonly used in any of these smaller forms.
  • The succession of parts is characterized by a relationship of keys, especially in the ternary forms--often tonic/dominant or tonic/relative major or minor.
  • There is a definite contrast in the nature of the thematic material between the first and second parts, and in ternary form, a return in the third part to the material of the first part.

Binary Form

  1. The general format of binary form is statement/contrast, designated by the letters AB.  Each binary piece, however, will have its own particular characteristics in regard to the use of smaller forms, key relationships, etc.
  • The use of the prime symbol ('), as in a', indicates an "a" phrase which is similar, but not identical, to the original "a" phrase.  Similarly, A' indicates a section similar to A.
  1. The two sections of binary form are usually repeated: 
  ||:    A    :|| ||:    B    :||
Major I     -     V V     -     I
Minor i     -     III III     -     i
  1. A section is designated "closed" if it cadences on the tonic of the composition (the original tonic), and "open" if it cadences elsewhere.
  • In many binary forms the first section (A) is open, concluding with a half cadence or moving to a related key, while the second section (B) concludes with a perfect authentic cadence on the tonic.

Rounded Binary Form

  1. Rounded binary form differs from true binary form in that the first section (A) is repeated (sometimes in part) at the end of the second section (B), e.g., ABa.
  • Theorists sometimes refer to rounded binary (the "rounding out" at the close with a short return of the original material) as incipient ternary; "incipient" meaning "beginning to appear."  Either term may be used, although rounded binary will be our preferred term.

Ternary Form

  1. The general format of ternary form is statement/contrast/restatement, designated by the letters ABA.  As with binary form, each piece will have its own internal characteristics with regard to key relationships and other smaller forms.
  1. Ternary form is more readily distinguishable from rounded binary when the third section (A) is more balanced with the first in terms of length and importance of the structure as a whole.  Thus, the third part is usually at least an eight-measure period, and is often extended.
  1. The A sections of three-part forms are typically "closed" in formal design, i.e., they cadence on the tonic.

Da Capo Ternary Form

  1. This form is created merely by placing the direction "D.C. al fine" at the end of the B section.  The fine, then, is placed at the end of the first A section, thereby, constituting and ABA form without having to rewrite the first A section.

Ternary Form Written Out

  1. One advantage of writing out the final A section is that the composer may wish to vary the material of the opening A section at the conclusion of the work.

Expansion of the Middle Section

  1. In the more simple ABA forms, the B section often appears to function more or less as a transition between the opening and closing A sections.  The middle section, however, can assume equal or greater importance than its surrounding A sections.

Larger Ternary Forms (Composite)

  1. It is possible for the three sections of ternary form to be comprised of forms within themselves.  For example:
A B A   A B A

These forms would be referred to as composite ternary forms.  (Composite can refer to any form in which other smaller forms are present within.)

The second example is commonly found in Da Capo ternary form.


  1. Sonata form--a composition with three main sections: exposition, development, and recapitulation.  (The term sonata also refers to all movements of a multi-movement composition, e.g., Piano Sonata in C Major.)
  1. Exposition:  the purpose of this section is to "expose" or state the thematic material upon which the entire movement is based.
  • Theme 1:  in the tonic key
  • (Theme Group 1:  Sometimes Theme 1 is not a single melody, but a group of melodic ideas that form a "theme group.")
  • Transition:  prepares for the 2nd Theme, which is traditionally in a related key.  The transition may contain material from:  the 1st Theme/Theme Group, the 2nd Theme/Theme Group, a combination of the two, or unrelated material.
  • Theme 2:  typically contrasts with the first.  In major keys, it is most often in the dominant key.  In minor keys, it is often in the dominant minor, or relative major (most common).
  • Monothematic:  earlier sonata forms often have only one theme, the 2nd Theme merely being the first theme transposed.
  • Theme 3:  some movements in sonata form of extended length often contain a 3rd Theme, the closing theme, usually in the same key as the 2nd, but it is preceded by a transition.
  • Codetta:  to complete the exposition, a codetta (small coda) is sometimes included.  It has the characteristics of an extended cadence, and may or may not recall 1st Theme material.
  1. Development this section provides opportunity for motivic development of material presented in the exposition.  Many key possibilities are seen in development sections.
  • Techniques:  sequence, modulation, augmentation, diminution, change of mode, fragmentation (selecting fragments from previous material).
  • Form:  no set pattern exists, however, identifiable subsections may be noted.
  • Retransition:  the final section of the development, which prepares for the recapitulation.
  1. Recapitulation:  return to the tonic and to themes stated in the exposition--provides balance to the movement.
  • Return of Theme 1 / Theme Group 1:  These themes appear in the original key.  (Exception:  In some early sonata forms, the recap begins in the subdominant, and is essentially a transposition of the exposition.)
  • Return of the transition:  In the recap, it loses some of its reason for being, because it does not support a modulation, although some chromaticism may be present.  If a change of key occurs (the exception), a return to the tonic causes the transition to be longer than in the exposition.
  • Return of Theme 2: In major keys:  Theme 2 is in the tonic key.  In minor keys:  Theme 2 is in the tonic or parallel major key.
  • Return of Theme 3:  If there is a Theme 3, it appears in the tonic.  When Theme 2 (in minor) is cast in the parallel major, however, Theme 3 may do the same.
  • Return of Codetta: If there is one, it appears in the tonic key.

Optional Sections

  1. An Introduction may appear prior to Theme 1.
  1. A Coda of varying length may appear following the recapitulation.

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