A section is the building block of musical form.

A section contains one or more phrases and forms a coherent musical entity.

We could be more precise about what a section is and differentiate it from a phrase and from other terms used in form such as segment, passage, figure, arrangement, and movement. However, there is little consistency in the use of these terms or even whether they are synonyms for one other. To avoid confusion we will use just the one word, section.

By convention, a section is labelled with a capital letter. The first section is always labelled A. Other sections are labelled B, C and so on. If a section is varied or tweaked in some way it is labelled with a number. For example, A1 refers to a section which is a variant of section A.

A special section can be tagged onto the beginning and end of a piece of music. A start section is sometimes called an overture, an end section is a coda. Here are some common techniques for starts and ends:

  • Start and end abruptly. You can dive straight in at the deep end and start immediately. You can end abruptly when you run out of steam. These are the simplest ways to top and tail a piece of music.
  • Be provocative and start a section in a different key to the rest of the piece. Do the same at the end.
  • Start with a climax, an upward movement in pitch and an increase the volume. End with an anticlimax, a downward movement in pitch and a reduction of volume. Use a single (anti)climax or multiple (anti)climaxes. Insert either or both of these sections during a piece of music to clearly separate one section from another.
  • Fade in or out. A fade is a gradual increase or decrease in volume. Fade in to start a piece, fade out to end it.
  • End with a retrograde (backwards) version of the start.