@Patrx2 I'm taking a music class and learning about the different forms. They use terms like ABA. Does this notation refer to that fact that we are switching from emphasis on the tonic to the dominat...or something like that? I just don't get what A or B signifie. But it occurred to me that it might denote which roman numeral you are in. Am I correct? Sorry if that was jumbled

@StanShunpike "A" is a well-defined section of music: it may be use single theme, or a closely tied-together succession of themes, but it is marked by a clear cadential boundary. "B" is a contrasting section with its own clear cadential boundary.

The thematic material does not necessarily need to be different: Baroque binary form dances commonly use the same material in each section, but A is contrasted to B by moving from the tonic to a clear dominant cadence, whereas B moves from the dominant to a clear tonic cadence.

In ABA, (simple ternary) the materials might articulate a theme in the tonic, a contrasting theme in a different key, and a return of the first them in the tonic again. It is the articulation of clear sections that counts.

There are limits to this particular way of viewing musical form, needless to say. I used to see a lot of work that very neatly articulated all the As, Bs and Cs, and turned out square and lifeless as a result - we tended to call it cookie-cutter form.

@Patrx2 i never have used it and I like my songs a lot. Does that mean it is a hindrance to think in such terms?

@StanShunpike Not entirely. There is a lot of music that falls quite naturally into sections, and the terminology can be useful in discussing such music. The danger is that, having labelled all the As, Bs and Cs, one's thinking about form stops right there.

@Patrx2 so are fugues an example of something that fits nicely into sections?

The minuet-trio-minuet I can see. And also sonata-allegro form.

@StanShunpike It depends. Fugues are normally through-composed - very seldom a strong sense of sections or of any really strong cadences until the very end. There are sectional fugues - most canzonas fit the bill. Sonata-allegro is trickier - yes, most arrivals at new themes and harmonic areas in a sonata movement are events, but the same taste for drama that led to the form means that these events can be ambiguous or smeared in time.

In music, it isn't that there are sections that is important; it's why they're there, and why they take the form they do. Enumerating As, Bs and Cs tends to overlook that.