Timbre refers to the quality or characteristic sound of a musical instrument, voice, or group of instruments. It is often described as the color or tone of the sound and can be used to distinguish between different types of instruments or voices. Timbre is influenced by factors such as the size, shape, and material of an instrument's body, the length and tension of its strings, and the type of wood used in a stringed instrument. In vocal music, timbre is affected by factors such as range, resonance, and vibrato.