What term describes a piece of music's conclusion or final section?

The term that describes a piece of music's conclusion or final section is known as the "Coda." In music composition, the coda serves to bring a sense of closure to the work, often by revisiting themes or motifs that have been presented earlier in the piece. It provides a final statement that wraps up the musical ideas, allowing listeners to feel a resolution after the journey of the composition.

The other terms refer to different sections of a musical structure. The exposition introduces the main themes, the development explores and transforms those themes, and the recapitulation brings the original themes back, usually after they have been altered during the development phase. In contrast, the coda specifically marks the end, offering a satisfyingly conclusive end point to the music.