What is an "exposition" in a fugue?

In a fugue, the "exposition" is the opening section where each voice presents the subject. This is a crucial part of the fugue structure, as it introduces the main theme that will be developed and explored throughout the piece. During the exposition, the subject is typically stated in one voice, and then subsequent voices enter sequentially, each presenting the subject in turn, often in different keys or registers.

This structure establishes the primary material of the work and sets the stage for the exploration and variation that will follow in later sections, such as the development. The clarity of the exposition is essential, allowing listeners to grasp the thematic content and recognize how it will be manipulated in the subsequent sections of the fugue. Understanding this foundational aspect of fugue form is key to appreciating how composers skillfully elaborate on musical ideas within their works.