What is a Fugue in music?

A fugue is a complex musical composition characterized primarily by the development of one or more themes through imitative counterpoint. In a fugue, the main theme, known as the subject, is introduced in one voice and then imitated by other voices at different pitches and in different keys, creating a rich tapestry of sound. This technique of imitation is a hallmark of contrapuntal writing, which is central to the fugue structure.

Fugues often have distinct sections, including an exposition where the subject is presented, followed by episodes where the subject might be developed or varied, but always with an emphasis on counterpoint. This intricate manipulation of themes allows for a depth and complexity in the music that is highly regarded, especially in the Baroque era.

Understanding this structure is vital for recognizing the significance of the fugue within the broader context of Western classical music, especially in works by composers like Johann Sebastian Bach, who is a quintessential example of fugue mastery. The other options do not capture this fundamental aspect of imitative counterpoint, thus missing the essence of what defines a fugue.