What does "primo" signify in a duet?

In the context of musical duets, "primo" refers to the first part or the upper part of the vocal or instrumental lines being performed. This term is often contrasted with "secondo," which indicates the second part or lower line. In a duet, the primo typically carries the melody or primary thematic material, making it a significant and often more prominent role in the performance.

Understanding the role of primo in a duet helps performers interpret the music correctly, allowing them to balance their contributions effectively with the secondo. It is essential in defining the structure and harmony of the piece, ensuring that the musical conversation between the parts is engaging and cohesive.