tanbark

The bark of various trees used as a source of tannin.

Shredded bark from which the tannin has been extracted, used to cover circus arenas, racetracks, and other surfaces.

The bark of the oak (or other trees) used as a source of tannin

The spent bark used as a ground covering

bark rich in tannin; bruised and cut in pieces to use for tanning; spent tanbark used as a ground covering