In fugue, what does the term 'exposition' refer to?

In the context of a fugue, the term 'exposition' specifically refers to the section at the beginning where the main theme, or subject, is introduced in a systematic way by each voice. During the exposition, each voice enters one after another, presenting the subject in the home key. This establishes the thematic material that will be developed throughout the rest of the fugue.

The other options touch on different aspects of a fugue but do not accurately define the term 'exposition.' A thematic development section refers to later parts of the fugue where the original themes are elaborated or transformed. Overlapping subjects could occur in the later sections or episodes but are not the defining feature of the exposition. Lastly, a transition to an episode describes a shift away from the main thematic material, which occurs after the exposition has been completed.