Timbre (4)
I believe the answer is:
tone
'timbre' is the definition.
(I know that timbre can be written as tone)
This is the entire clue.
(Other definitions for tone that I've seen before include "Musical sound; quality of hue" , "Sound - style" , "Theobald Wolf . . . ." , "Vocal sound of note" , "Quality or character of sound" .)