What is the term for music intended for a small ensemble, usually performed without a conductor?

The term for music intended for a small ensemble, usually performed without a conductor, is chamber music. This genre is characterized by its intimate setting, typically involving a small number of instruments, often ranging from two to around ten performers. The essence of chamber music lies in its collaborative nature, where each musician plays an integral role, and the music often emphasizes individual expression and communication among the players.

In contrast, symphonic music is designed for larger orchestras and typically involves a conductor to manage the performance of the ensemble. Solo music focuses on individual performers, while orchestral music refers to works designed for full orchestras, which also rely heavily on a conductor to coordinate the performance. These distinctions clarify why chamber music is the appropriate term for the context presented in the question.