tan

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To convert (an animal hide) into leather by subjecting it to a chemical process that stabilizes the proteins, making it less susceptible to decay.
• intransitive verb To make (a person or a person's skin) darker by exposure to the sun.
• intransitive verb Informal To thrash; beat.
• intransitive verb To become darker from exposure to the sun.
• noun A light or moderate yellowish brown to brownish orange.
• noun A suntan.
• noun Tanbark.
• noun Tannin.
• noun A solution derived from tannin.
• adjective Light or moderate yellowish-brown to brownish-orange.
• adjective Having a suntan.
• adjective Used in or relating to tanning.
• abbreviation tangent

from The Century Dictionary.

• noun The term is often used to mean spent bark which has served for the manufacture of leather and is spread over streets to deaden the sound of vehicles, or over the floor of a riding-school or circus to diminish the danger of falls, or applied to clay land as a loosening material. It is also commonly used as fuel in tanneries.
• noun A Chinese unit of weight, a picul, equal to 133⅛ pounds avoirdupois.
• noun A Japanese measure of surface, equal to .245 of an acre.
• To prepare, as skins of animals, by soaking in some liquid containing tannic acid, which is generally obtained from the bark of some tree, oak-bark being commonly thought to be the best.
• By extension, to convert into leather by other means, as by the use of mineral salts (as those of iron and chromium), and even of oil or fat, as in the case of buckskin, chamois, and the like. See leather, taw, 2.
• To make brown; embrown by exposure to the rays of the sun.
• To deprive of the freshness of youth; impair the freshness and beauty of.
• To beat; flog; thrash.
• In the manufacture of so-called artificial marble, or an imitation of marble made from a mixture of gelatin and gum, to render (cast slabs of the mixture) hard and insoluble by steeping in a suitable preparation. See tannage, 3.
• To treat with some hardening process as a preservation from rot, as fish-nets.
• To be or become tanned: as, the leather tans easily.
• To become tan-colored or tawny: as, the face tans in the sun.
• noun The bark of the oak, willow, chestnut, larch, hemlock, spruce, and other trees abounding in tannin, bruised and broken by a mill, and used for tanning hides.
• noun A yellowish-brown color, like that of tan: as, gloves of gray or tan.
• noun An embrowning of the skin by exposure to the sun.
• Of the color of tan, or of a color approaching that of tan; yellowish-brown.
• noun A twig, or small switch.
• noun An obsolete Middle English contraction of taken, old infinitive or past participle of take.
• noun A Middle English contraction of to an.
• noun Same as fan-tan.
• noun An abbreviation of tangent.

from the GNU version of the Collaborative International Dictionary of English.

• noun See picul.
• adjective Of the color of tan; yellowish-brown.
• adjective See under Black, a.
• noun The bark of the oak, and some other trees, bruised and broken by a mill, for tanning hides; -- so called both before and after it has been used. Called also tan bark.
• noun A yellowish-brown color, like that of tan.
• noun A brown color imparted to the skin by exposure to the sun.
• noun (Hort.) a bed made of tan; a bark bed.
• noun the liquor used in tanning leather.
• noun a spud used in stripping bark for tan from trees.
• noun See Bark stove, under Bark.
• noun a vat in which hides are steeped in liquor with tan.
• transitive verb To convert (the skin of an animal) into leather, as by usual process of steeping it in an infusion of oak or some other bark, whereby it is impregnated with tannin, or tannic acid (which exists in several species of bark), and is thus rendered firm, durable, and in some degree impervious to water.
• transitive verb To make brown; to imbrown, as by exposure to the rays of the sun.
• transitive verb colloq. To thrash or beat; to flog; to switch.
• intransitive verb To get or become tanned.