In the arts, to convert animal skins into leather by steeping them in an infusion of oak or some other bark, by which they are impregnated with tannin, an astringent substance which exists in several species of bark, and thus rendered firm, durable, and in some degree, impervious to water.

To make brown; to imbrown by exposure to the rays of the sun; as, to tan the skin. His face all tann’d with scorching sunny rays.

The bark of the oakbruised and broken by a mill for tanning hides. It bears this name before and after it has been used. Tan, after being used in tanning, is used in gardening for making hotbeds; and it is also made into cakes and used as fuel.