Timbre
Etymology
From French "timbre," which earlier meant a small bell struck by a hammer, and before that a drum, from Medieval Latin and ultimately Greek "tympanon," "drum." The word for the sounding object came to name the quality of the sound it made. French adopted it as the technical term for tone-color, and English borrowed it whole.
noun · /TAM-bur/
The distinctive tonal color of a voice or instrument, apart from its pitch or loudness.
What it names
The quality that lets you tell a flute from a violin playing the same note, or recognize a friend’s voice in one syllable — a word for the character of a sound itself.
Example
It wasn’t the tune that moved her but the timbre of his voice — smoky, slightly cracked, unmistakably his.
Related idea
Timbre is the color or character of a sound; pitch is simply how high or low it is.