The character or quality of a sound, the unique tone color that distinguishes it from other sounds at the same pitch. The texture of the music, note-by-note or more generally.
For example:
Seu Jorge covering Life on Mars on a classical guitar. Bowie in full space shot mode. Same notes. Different timbres.

And also:
A woods with trees, rocks, trails, a stream, but different than another. Double entendre. Yes. But also the idea that places have textures and feelings, even when composed of the same elements, the Venn diagrams of species, sound and light overlapping almost completely.
For example.
Walden Woods circling a classic glacial kettle pond, pines growing right down to the water’s edge, wide trails, pounded out by a million visitors a minute. Right next door, Fairhaven Bay, really a wide stretch in the Sudbury River, the same pines undulating down to a weed clogged waterfront. No one around. Herons in the reeds. Water fowl drifting slowly on the current.
Tone color. Texture.
Back when I was still involved peripherally in bike design (i.e. I got to suggest names for new models), I wanted desperately to call a bike the Timbre, but that idea was always rejected because it’s not a homonym of timber. It’s pronounced tam’-bur. I thought that would just make the bike more intriguing, and I loved the idea that our bike was like others, but fundamentally different, of a finer texture.

I’m butchering the word, its meaning, but the concept of a thing, like woods, that can be composed of the same elements but strike a different tone is so appealing to me and gets at the way I feel in different places. I hear them differently.
For example:
I run the switchbacks beyond Beaver Brook, where the wooden bridge takes you from the easily accessible meadow to the scruffy low forest below the old state mental hospital. On the hill there’s a concrete water tower with rusted ladder hanging two-thirds down its side. Graffiti wraps it like technicolor frieze.
It’s a shitty place if you’re a person who likes nature more natural, or civilization more civilized, but it’s exactly the timbre of the place that appeals to me, simultaneously creepy, dangerous, beautiful. A dirt bag oasis. It captures the pathos of abandonment and the beauty of ruin, and the hope of people who want to make something of it, even as it crumbles back into the earth.