Online Etymology Dictionary

taciturn (adj.): "habitually silent," 1771, back-formation from taciturnity, or from French taciturne (15c.), from Latin taciturnus "not talkative, noiseless."
taciturnity (n.): mid-15c., from Middle French taciturnité, from Latin taciturnitatem (nominative taciturnitas) "a being or keeping silent," from taciturnus "disposed to be silent," from tacitus "silent" (see tacit).
tack (n.1): "clasp, hook, fastener," also "a nail" of some kind, c. 1400, from Old North French taque "nail, pin, peg" (Old French tache, 12c., "nail, spike, tack; pin brooch"), probably from a Germanic source (compare Middle Dutch tacke "twig, spike," Frisian tak "a tine, prong, twig, branch," Low German takk "tine, pointed thing," German Zacken "sharp point, tooth, prong"), from Proto-Germanic *tag-. Meaning "small, sharp nail with a flat head" is attested from mid-15c. The meaning "rope to hold the corner of a sail in place" is first recorded late 15c.
tack (n.2): "horse's harness, etc.," 1924, shortening of tackle (n.) in sense of "equipment." Tack in a non-equestrian sense as a shortening of tackle is recorded in dialect from 1777.
tack (n.3): "food" in general, but in dialect especially "bad food," and especially among sailors "food of a bread kind," 1833, perhaps a shortening and special use of tackle (n.) in the sense of "gear." But compare tack "taste" (c. 1600), perhaps a variant of tact.
tack (v.1): late 14c., "to attach" with a nail, etc., from tack (n.1). Meaning "to attach as a supplement" (with suggestion of hasty or arbitrary proceeding) is from 1680s. Related: Tacked; tacking.
tack (v.2): "turn a ship's course toward the wind at an angle," 1550s, from tack (n.1) in the ship-rigging sense (the ropes were used to move the vessel temporarily to one side or another of its general line of course, to take advantage of a side-wind); hence tack (n.) "course of conduct or mode of action suited to some purpose" (1670s), from figurative use of the verb (1630s). Related: Tacked; tacking.
tack-hammer (n.): 1848, from tack (n.1) + hammer (n.).
tackle (n.): mid-13c., "apparatus, gear," especially the rigging of a ship, from Middle Dutch or Middle Low German takel "the rigging of a ship," perhaps related to Middle Dutch taken "grasp, seize" (see take (v.)), or perhaps from root of tack (n.1), which, if not the origin, has influenced the sense. Meaning "apparatus for fishing" is recorded from late 14c. Meaning "device for grasping and shifting or moving" is from 1530s. Meaning "act of tackling" in the sporting sense is recorded from 1876 (see tackle (v.)); as the name of a position in North American football, it is recorded from 1884. Welsh tacl is fro English.
tackle (v.): mid-14c., "entangle, involve," from tackle (n.). Sense of "to furnish (a ship) with tackles" is from c. 1400; meaning "to harness a horse" is recorded from 1714. The meaning "lay hold of, come to grips with, attack" is attested from 1828, described by Webster that year as "a common popular use of the word in New England, though not elegant;" figurative sense of "try to deal with" (a task or problem) is from 1840. The verb in the sporting sense first recorded 1867, "to seize and stop." Related: Tackled; tackling.
tacky (adj.1): "sticky," 1788, from tack (n.1) in the sense of "an act of attaching temporarily" + -y (2). Related: Tackiness "stickiness."
tacky (adj.2): "in poor taste," 1888, from earlier sense of "shabby, seedy" (1862), adjectival use of tackey (n.) "ill-fed or neglected horse" (1800), later extended to persons in like condition, "hillbilly, cracker" (1888), of uncertain origin. Related: Tackiness.
The word "tacky" is a Southern colloquialism. It was coined by a wealthier or more refined and educated class for general application to those who were not sheltered by the branches of a family tree, who were "tainted." Those who were wealthy and yet had no great-grandfathers were "tackies." The word was used both in contempt and in derision. It is now nearly obsolete in both senses. There are no aristocrats in the South now, and therefore no "tackies." No man who has the instincts of a gentleman is spoken of as a "tacky," whether he can remember the name of his grandfather's uncle or not. But it has its uses. It is employed in describing persons of low ideas and vulgar manners, whether rich or poor. It may mean an absence of style. In dress, anything that is tawdry is "tacky." A ribbon on the shopkeeper's counter, a curtain in the bolt, a shawl or bonnet, a bolt of cloth fresh from the loom may be "tacky," because it is cheap and yet pretentious. In Louisiana the inferior grade of Creole ponies are known as "tackies." [Horace Ingraham, Charleston, S.C., in "American Notes and Queries," Feb. 15, 1890]
taco (n.): tortilla filled with spiced meat, etc., 1949, from Mexican Spanish, "light lunch," literally "plug, wadding."
Tacoma: city in Washington State, U.S., from Lushootseed (Salishan) /tequbed/ "snow-covered mountain," in reference to nearby Mount Rainier.
Taconic: mountain range in New England, perhaps from Mahican (Algonquian) */ta:hkenek/ "in the woods;" compare Unami Delaware (Algonquian) /tekenink/ "in the woods."
tact (n.): 1650s, "sense of touch or feeling" (with an isolated instance, tacþe from c. 1200), from Latin tactus "a touch, handling, sense of touch," from root of tangere "to touch" (see tangent (adj.)). Meaning "sense of discernment in action or conduct, diplomacy, fine intuitive mental perception" first recorded 1804, from development in French cognate tact. The Latin figurative sense was "influence, effect."
tactful (adj.): 1844, from tact + -ful. Related: Tactfully; tactfulness.
tactic (n.): 1766, from Modern Latin tactica, from Greek taktike (tekhne) "(art of) arrangement," from fem. of taktikos "pertaining to arrangement" (see tactics). Earlier it meant "a tactician" (1630s), and was in use as an adjective meaning "tactical" (c. 1600).
tactical (adj.): 1560s, "pertaining to tactics," from Modern Latin tactica (see tactics) + -al (1). Meaning "characterized by adroit management" is from 1883. In reference to nuclear weapons ("for limited use in military operations," opposed to strategic) it is recorded from 1957. Related: Tactically.
tactician (n.): "expert in tactics," 1761, from tactic + -ian.
tactics (n.): 1620s, "science of arranging military forces for combat," from Modern Latin tactica (17c.), from Greek taktike techne "art of arrangement," noun use of fem. of taktikos "of or pertaining to arrangement," especially "tactics in war," adjective to taxis "arrangement, an arranging, the order or disposition of an army, battle array; order, regularity," verbal noun of tassein "arrange," from PIE root *tag- "to set aright, set in order" (see tangent).
tactile (adj.): 1610s, "perceptible to touch," from French tactile (16c.) and directly from Latin tactilis "tangible, that may be touched," from tactus, past participle of tangere "to touch" (see tangent (adj.)). Meaning "of or pertaining to the sense of touch" is attested from 1650s. Related: Tactility.
tactless (adj.): "characterized by want of tact," 1830, from tact + -less. Related: Tactlessly; tactlessness.
tactual (adj.): "pertaining to the sense of touch," 1640s, from Latin tactus "a touch" (see tact) + -al (1).
tad (n.): 1877, "young or small child," probably a shortened form of tadpole, which is said to be the source of Tad as the nickname of U.S. President Lincoln's son Thomas (1853–1871). The extended meaning "small amount" is first recorded 1915.
tadpole (n.): mid-15c., from tadde "toad" (see toad) + pol "head" (see poll (n.)).
tae: a Scottish form of to.
tae kwon do: 1967, from Korean, said to represent tae "kick" + kwon "fist" + do "art, way, method."
taedium vitae: Latin, "weariness of life; a deep disgust with life tempting one to suicide."
taffeta (n.): mid-14c., "fine, smooth, lustrous silk cloth," also taffata, from Old French taffetas (early 14c.), from Italian taffeta or Medieval Latin taffata, ultimately from Persian taftah "silk or linen cloth," noun use of past participle of taftan "to twist, spin, weave, interlace," from Iranian *tap-. Applied to different fabrics in different eras (and see tapestry).
taffrail (n.): 1814, alteration of tafferel (1704) "upper panel on the stern of a ship (often ornamented)," earlier, "a carved panel" (1620s), from Dutch tafereel "panel for painting or carving," dissimulation from *tafeleel, diminutive of tafel "table," from the general West Germanic borrowing of Latin tabula "slab, board" (see table (n.)). The word developed in Dutch from the custom of ornamenting (by painting or carving) the high, flat stern of old sailing ships; spelling and sense altered in English by influence of rail (n.).
taffy (n.): coarse candy made from sugar or molasses boiled down and cooled, 1817, related to toffee, but of uncertain origin; perhaps associated with tafia (1763), a rum-like alcoholic liquor distilled from molasses, presumably of West Indian or Malay origin (perhaps a Creole shortening of ratafia). On this theory, the candy would have been made from the syrup skimmed off the liquor during distillation.
Taffy: characteristic name of a Welshman, c. 1700, from Teifi, Welsh form of Davy (see David).
Taft: surname, from a variant of Old English toft "homestead, site of a house."
tag (n.2): "children's game," 1738 (in reference to "Queen Mary's reign"), perhaps a variation of Scottish tig "touch, tap" (1721), probably an alteration of Middle English tek "touch, tap" (see tick (n.2)). Baseball sense is from 1912.
tag (v.1): "to furnish with a tag," late 14c. (implied in tagged), from tag (n.1). Meaning "go along as a follower" is from 1670s; sense of "follow closely and persistently" is from 1884. Related: Tagging. Verbal phrase tag along is first recorded 1900.
tag (v.2): "a touch in the game of tag," 1878; in baseball, 1904, from tag (n.2); the adjective in the pro-wrestling sense is recorded from 1955. Related: Tagged; tagging.
tag (n.1): "small, hanging piece from a garment," c. 1400, of uncertain origin but probably from a Scandinavian source (compare Norwegian tagg "point, prong, barb," Swedish tagg "prickle, thorn") and related to Middle Low German tagge "branch, twig, spike"), from Proto-Germanic *tag-. The sense development might be "point of metal at the end of a cord, string, etc.," hence "part hanging loose." Or perhaps ultimately from PIE *dek-, a root forming words referring to fringe, horsetail, locks of hair" (see with tail (n.1)).

Meaning "a label" is first recorded 1835; sense of "automobile licence-plate" is recorded from 1935, originally underworld slang. Meaning "an epithet, popular designation" is recorded from 1961, hence slang verb meaning "write graffiti in public places" (1990).
Tagalog (n.): people living near Manila in the Philippines, also their language, 1704, from Tagalog taga "native to" + ilog "river."
tagliatelle (n.): 1876, from Italian tagliatelle, plural noun from tagliare "to cut" (see entail).
tagline (n.): "punchline of a joke," 1926, originally "last line in an actor's speech" (1916), from tag (n.1) + line (n.).
tahini (n.): from Arabic tahina, from tahana "to grind or crush."
Tahiti: from native Polynesian Otahiti, of uncertain meaning. It was called in turn Sagittaria (1606, by the Portuguese), King George III Island (1767, by the British), Nouvelle-Cythère (1768, by the French). Related: Tahitian.
Tahoe: Lake on the Nevada-California border, from Washo /da'aw/ "lake."
Tai (n.): group of people of related ethnicity and language in Southeast Asia, including the Thai, Lao, and Shan, from tai, literally "free."
tai chi (n.): 1736, the "supreme ultimate" in Taoism and Neo-Confucianism, from Chinese tai "extreme" + ji "limit." As the name of a form of martial arts training (said to have been developed by a priest in the Sung dynasty, 960-1279) it is first attested 1962, in full, tai chi ch'uan, with Chinese quan "fist."
taiga (n.): belt of coniferous forests in Siberia, 1869, from Russian taiga, which is of Mongolian origin.
tail (n.1): "hindmost part of an animal," Old English tægl, tægel "a tail," from Proto-Germanic *tagla- (source also of Old High German zagal, German Zagel "tail," dialectal German Zagel "penis," Old Norse tagl "horse's tail," Gothic tagl "hair"), from PIE *doklos, from suffixed form of root *dek- (2) "something long and thin" (referring to such things as fringe, lock of hair, horsetail; source also of Old Irish dual "lock of hair," Sanskrit dasah "fringe, wick"). According to OED, the primary sense, at least in Germanic, seems to have been "hairy tail," or just "tuft of hair," but already in Old English the word was applied to the hairless "tails" of worms, bees, etc. But Buck writes that the common notion is of "long, slender shape." As an adjective from 1670s.

Meaning "reverse side of a coin" (opposite the side with the head) is from 1680s; that of "backside of a person, buttocks" is recorded from c. 1300; slang sense of "pudenda" is from mid-14c.; that of "woman as sex object" is from 1933, earlier "act of copulation" with a prostitute (1846). Of descending strokes of letters, from 1590s.

Tails "coat with tails" is from 1857. The tail-race (1776) is the part of a mill race below the wheel. To turn tail "take flight" (1580s) originally was a term in falconry. The image of the tail wagging the dog is attested from 1907. Another Old English word for "tail" was steort (see stark).
tail (n.2): "limitation of ownership," a legal term, early 14c. in Anglo-French; late 13c. in Anglo-Latin, in most cases a shortened form of entail.
tail (v.): 1520s, "attach to the tail," from tail (n.1). Meaning "move or extend in a way suggestive of a tail" is from 1781. Meaning "follow secretly" is U.S. colloquial, 1907, from earlier sense of "follow or drive cattle." Related: Tailed; tailing. Tail off "diminish" is attested from 1854.