Section 24.2 Sectional versus Continuous
We apply the descriptor “sectional” to a binary or ternary form when the first section (the A section) ends on the tonic. (Note: We use lowercase letters to refer to phrases and uppercase letters to refer to sections.)
The term “continuous” is used the first section of a binary or ternary form does not end on the tonic chord. While this often means the first section ends in a new key, it can also mean the first section ends on the dominant chord in a half cadence.
In naming any binary or ternary form, use the terms sectional or continuous before binary or ternary, for example “sectional binary,” “continuous binary,” “sectional ternary,” or “continuous ternary.”
Other descriptors include “two-reprise,” which means both the first section (the A section) and second section (the A’ or B section) are repeated, and “rounded,” used in conjunction with binary (“rounded binary”) to specify that the opening material returns after the contrasting section.
In the following sections we will discuss three types of binary forms:
“Simple” Binary (usually called “binary”)