Final answer:
Timbre refers to the perceived uniqueness of a sound, determined by a combination of frequencies and intensities that give a sound its distinctive tone quality.
Step-by-step explanation:
Timbre refers to the perceived uniqueness of a sound. It is the combination of frequencies and intensities that gives a sound its distinctive tone quality. It is more difficult to quantify timbre compared to loudness or pitch as it is a subjective perception influenced by higher-level processes in the brain.