What is an "introduction" in a musical composition?

An introduction in a musical composition serves as a preliminary section that sets the stage for the main themes and ideas that will be explored throughout the piece. It often establishes the mood, tempo, and key, providing listeners with a sense of what to expect as the composition unfolds. This section may introduce motifs or harmonic material that will later be developed and varied throughout the work, creating a cohesive musical narrative.

Introductions play a crucial role in preparing the audience, enhancing their understanding and engagement with the piece that follows. By contrasting with the other sections of the work, such as the main body or conclusion, the introduction establishes a framework that can be expanded upon, transformed, or resolved at later stages.