late Old English tannian "to convert hide into leather" (by steeping it in tannin), from Medieval Latin tannare "tan, dye a tawny color" (c. 900), from tannum "crushed oak bark," used in tanning leather, probably from a Celtic source (such as Breton tann "oak tree"). The meaning "make brown by exposure to the sun" (as tanning does to hides) first recorded 1520s; intransitive sense also from 1520s. Of persons, not considered an attractive feature until 20c.; in Shakespeare, "to deprive of the freshness and beauty of youth" (Sonnet CXV). As an adjective from 1620s. To tan (someone's) hide in the figurative sense is from 1660s. Related: Tanned; tanning. German Tanne "fir tree" (as in Tannenbaum) might be a transferred meaning from the same Celtic source.

"bronze color imparted to skin by exposure to sun," 1749, see tan (v.). Earlier as "substance made of crushed bark used in making leather" (c. 1600). As a simple name for a brownish color, in any context, it is recorded from 1888. The adjective meaning "of the color of tanned leather" is recorded from 1660s. Tan-line attested from 1979.

"one who tans leather," Old English tannere, agent noun from tannian (see tan (v.)).

c. 1400, "process of tanning," from Old French tannerie (13c.) or a native formation from tan (v.) + -ery. Meaning "place where tanning is done" is from 1736, perhaps from tanner (n.1) + -y (2).

late 15c., "process of tanning leather," verbal noun from tan (v.). Intransitive sense "process of getting suntan" is from 1944. Tanning booth is attested by 1978; tanning bed by 1981.

"tan-colored," late 14c., from Anglo-French tauné "of or like the brownish-yellow of tanned leather," from Old French tanét "dark brown, tan" (12c., Modern French tanné), past participle of taner "to tan hides," from Medieval Latin tannare (see tan (v.)).Related: Tawniness.

"tannic acid, vegetable substance capable of converting animal hide to leather," 1802, from French tannin (1798), from tan "crushed oak bark containing tannin" (see tan (v.)). Tannic acid first recorded 1836, from French acide tannique, inroduced 1834 by French chemist Théophile-Jules Pelouze (1807-1867).

also sun-tan, 1821, from sun (n.) + tan (v.). Related: Suntanned; suntanning. As a noun from 1888. Originally an indication of outdoor laboring; considered as an enhancement to beauty or proof of idleness from 1920s: F.L. Allen, chronicler of the decade ("Only Yesterday"), notes 1929 as the year that "on the sands of a thousand American beaches, girls pulled down the shoulder-straps of their bathing suits to acquire fashionably tanned backs ...."

Estonian capital, from Old Estonian (Finnic) tan-linn "Danish fort," from tan "Danish" + linn "fort, castle." Founded 1219 by Danish king Valdemar II.

type of Japanese poem, 1877, from Japanese tanka, from tan "short" + ka "song."