What is the term for music that is written to be performed by multiple instruments or voices?

The term used for music that is written to be performed by multiple instruments or voices is "Composition." A composition is a complete piece of music that can include various elements such as melody, harmony, and rhythm, which are organized to create a distinct musical work. This term encompasses all forms of written music, whether for a small ensemble, an orchestra, or vocals, highlighting the collaborative nature of these works that often involve multiple performers interacting with one another.

While "score" refers to the written notation of a composition, and "arrangement" pertains to adapting a piece for a specific set of instruments or voices, these terms are more specialized and do not serve as general identifiers for music created for multiple performers. "Solo," in contrast, indicates a piece designed for a single performer, making it completely different from the concept of collaborative music-making inherent in a composition.