**Simple ternary form** is a formal type divided into three main parts, each a self-contained phrase, period, or phrase group.^[Steven G. Laitz and Christopher A. Bartlette, *Graduate Review of Tonal Theory: A Recasting of Common-Practice Harmony, Form, and Counterpoint* (New York: Oxford University Press, 2010), 197–204.] The outer parts state and restate the same material in the tonic key, while the middle part provides contrast, producing a *statement—digression—return*: $ \text{A}\quad\text{B}\quad\text{A}^{\prime} $ Unlike binary form, ternary form does not depend on repetition; repeats occasionally appear but are not a feature of the design. ## Tonal organization Ternary forms may be *full sectional*, *sectional*, or *continuous* according to whether the A section and the B section are tonally closed. In the diagrams below, the superscripts 1 and 2 indicate closed and open sections, respectively. The final section is labeled A′ throughout, distinguishing the return from the opening statement whether or not its material is altered. If both the A section and the B section close with a PAC, the form is considered *full sectional*: $ \text{A}^{1}\quad\text{B}^{1}\quad\text{A}^{\prime 1} $ If only one of them closes, the form is considered *sectional*. Most often it is the B section that remains open: $ \text{A}^{1}\quad\text{B}^{2}\quad\text{A}^{\prime 1}\text{ (more common)}\qquad\text{or}\qquad\text{A}^{2}\quad\text{B}^{1}\quad\text{A}^{\prime 1}\text{ (less common)} $ If neither closes, the form is considered *continuous*. The tonal motion finds its resolution only in the final section: $ \text{A}^{2}\quad\text{B}^{2}\quad\text{A}^{\prime 1} $ Either section may also fail to close without modulating, as when its cadence is evaded or broken off. ## Connective and post-cadential material Transitions and bridges are common in ternary forms and are not a feature of binary designs. A transition modulates; a bridge does not, and will occur where two sections are related by parallel mode. Material leading back to the return of A is termed a retransition. Any of the three sections may conclude with post-cadential material: a codetta, a cadential extension, or, at the close of the form, a coda.