(1) The perceived quality of a sound, unrelated to pitch or amplitude. Timbre is determined by how many harmonics are present in the sound, their frequencies, and how loud each is in relation to the fundamental frequency, and how the relative amplitudes of those harmonics change over time. The initial and ending transients of a tone have more to do with the timbre of a tone than its harmonic content. Also referred to as tone color.
(2) One of the building blocks of a patch in a Roland synthesizer.