Fugue

A fugue is built from a single short melodic idea, called the subject, which is introduced by one voice alone and then imitated, in turn, by each other voice in the texture — each new entrance typically starting while the previous voices continue on with related material. The word comes from the Latin fuga, "flight" or "chase," which is a fair description of what it sounds like: one idea, pursued through the texture.

Fugues are the high point of counterpoint — the technique of combining multiple independent melodic lines so they work together harmonically. Writing a good fugue is often treated as a serious test of compositional craft, since the composer has to keep a single idea coherent and interesting across every voice simultaneously.

Johann Sebastian Bach is the composer most associated with the form — his Well-Tempered Clavier is a landmark collection pairing a prelude and fugue in every major and minor key.

Where to start listening: Bach's "Little" Fugue in G minor is a compact, clear example of the subject entering one voice at a time; listen for the same short melodic idea reappearing throughout.