The impression of a sound based upon its harmonic spectrum and envelope, i.e.. the distinctness of a sound that allows a person to differentiate it from other sounds. For example, when you hear a guitar, cymbal, or violin, each has a unique set of harmonics (therefore, tonal quality) that identifies it as a particular instrument.
TIMBRE
Meaning of TIMBRE in English
Guitar English glossary. Английский словарь гитарных терминов . 2012