Online Etymology Dictionary

Tudor: 1779, from Welsh surname Tewdwr, used of the line of English sovereigns from Henry VII to Elizabeth I, descended from Owen Tudor, who married Catherine, widowed queen of Henry V. Applied from 1815 to a style of architecture prevalent during these reigns. The name is the Welsh form of Theodore.
Tuesday: Old English Tiwesdæg, from Tiwes, genitive of Tiw "Tiu," from Proto-Germanic *Tiwaz "god of the sky," differentiated specifically as Tiu, ancient Germanic god of war, from PIE root *dyeu- "to shine" (see diurnal). Cf. Old Norse tysdagr, Swedish tisdag, Old High German ziestag.

The day name (second element dæg, see day) is a translation of Latin dies Martis (cf. Italian martedi, French Mardi) "Day of Mars," from the Roman god of war, who was identified with Germanic Tiw (though etymologically Tiw is related to Zeus), itself a loan-translation of Greek Areos hemera. In cognate German Dienstag and Dutch Dinsdag, the first element would appear to be Germanic ding, þing "public assembly," but it is now thought to be from Thinxus, one of the names of the war-god in Latin inscriptions.
tufa (n.): "a porous rock," 1770, from Italian tufa "tufa, porous rock," probably from Latin tufus, tophus "loose, porous volcanic rock," said to be an Oscan-Umbrian loan-word.
tuff (adj.): advertiser's spelling of tough (adj.), attested by 1940.
tuffet (n.): 1550s, "little tuft," from Old French touffel (with exchange of diminutive suffix -et for French -el), diminutive of touffe (see tuft). Obsolete except in the nursery rhyme "Little Miss Muffet" (1843), where it has been felt to mean "hassock, footstool."
LITTLE Miss Muffet
Sat on a tuffet
And made of her knees such display
That the old fashioned spider,
Embarrassed beside her,
Was actually frightened away!

[Life Oct. 1, 1927]
tuft (n.): late 14c., perhaps from Old French touffe "tuft of hair," either from Late Latin tufa "a kind of crest on a helmet" (also found in Late Greek toupha), or from a Germanic source (cf. Old High German zopf, Old Norse toppr "tuft, summit;" see top (n.1)).
tug (v.): early 13c., from weak grade of Old English teohan "to pull, drag," from Proto-Germanic *teukh- "pull," from PIE *deuk- "to pull, to lead" (see duke (n.)). Related to tow (v.). Related: Tugged; tugging.
tug (n.): c.1500, from tug (v.). Meaning "small steamer used to tow other vessels" is recorded from 1817. Phrase tug of war (1670s) was originally figurative, "the decisive contest, the real struggle."
tugboat (n.): 1832, from tug (n.) + boat (n.).
Tuileries: former palace in Paris, begun by Catherine de Medici, 1564; so called because it was built on the site of an ancient tile-works, from Old French tieule "tile," from Latin tegula (see tile (n.)). The former residence of the royal court, it was destroyed by fire in 1871 and now is the site of the Jardin des Tuileries.
tuition (n.): mid-15c., "protection, care, custody," from Anglo-French tuycioun (late 13c.), from Old French tuicion "guardianship," from Latin tuitionem (nominative tuitio) "a looking after, defense, guardianship," from tuitus, past participle of tueri "to look after" (see tutor). Meaning "action or business of teaching pupils" is recorded from 1580s. The meaning "money paid for instruction" (1828) is probably short for tuition fees, in which tuition refers to the act of teaching and instruction.
tulip (n.): 1570s, via Dutch or German tulpe, French tulipe "a tulip," all ultimately from Turk. tülbent "turban," also "gauze, muslin," from Persian dulband "turban;" so called from the fancied resemblance of the flower to a turban.

Introduced from Turkey to Europe, where the earliest known instance of a tulip flowering in cultivation is 1559 in the garden of Johann Heinrich Herwart in Augsburg; popularized in Holland after 1587 by Clusius. The full form of the Turkish word is represented in Italian tulipano, Spanish tulipan, but the -an tended to drop in Germanic languages, where it was mistaken for a suffix. Tulip tree (1705), a North American magnolia, so called from its tulip-shaped flowers.
tulle (n.): fine silk bobbin-net, c.1818, from Tulle, town in central France, where the fabric was first manufactured.
tumble (n.): 1716, from tumble (v.).
tumble (v.): c.1300, "to perform as an acrobat," also "to fall down," perhaps from a frequentative form of Old English tumbian "dance about," of unknown origin. Related to Middle Low German tummelen "to turn, dance," Dutch tuimelen "to tumble," Old High German tumon, German taumeln "to turn, reel." Related: Tumbled; tumbling. Tumble-down (1791) originally meant "habitually falling down" and was used first of horses; sense of "in a dilapidated condition" is recorded from 1818.
tumbler (n.): mid-14c., "acrobat," agent noun from tumble (v.). A fem. form was tumbester (late 14c.). Meaning "drinking glass" is recorded from 1660s, originally a glass with a rounded or pointed bottom which would cause it to "tumble," and thus it could not be set down until it was empty.
tumbleweed (n.): also tumble-weed, 1887, from tumble (v.) + weed (n.).
tumbrel (n.): mid-15c., "two-wheeled cart," earlier an instrument of punishment of uncertain type (early 13c.), from Old French tumberel "dump cart," from tomber "(let) fall or tumble," possibly from a Germanic source (cf. Old Norse tumba "to tumble," Old High German tumon "to turn, reel;" see tumble). Notoriously used to take victims to the guillotine during the Reign of Terror.
tumescence (n.): 1725, from French tumescence, from Latin tumescentem (nominative tumescens) "swelling," present participle of tumescere "begin to swell," from tumere "to swell" (see thigh) + inchoative suffix -escere. The earliest attested form of the word in English is tumefaction (1590s).
tumescent (adj.): 1806, from Latin tumescentem, present participle of tumescere "to begin to swell," inceptive of tumere "to swell" (see thigh).
tumid (adj.): "morbidly swollen," 1540s, from Latin tumidus, from tumere "to swell" (see thigh). Figurative sense (in reference to prose, etc.) is attested from 1640s.
tummy (n.): 1867, infantile for stomach. Tummy-ache is attested from 1874.
tumor (n.): 1540s, from Latin tumor "swelling, condition of being swollen," from tumere "to swell" (see thigh).
tumulous (adj.): 1727, from Latin tumulosus, from tumulus (see tumulus).
tumult (n.): early 15c., from Old French tumulte (12c.), from Latin tumultus "commotion, disturbance," related to tumere "to be excited, swell" (see thigh).
tumultuous (adj.): 1540s, from Old French tumultuous (Modern French tumultueux), from Latin tumultuosus, from tumultus (see tumult). Related: Tumultuously.
tumulus (n.): ancient burial mound, 1680s, from Latin tumulus "hillock," from tumere "to swell" (see thigh).
tun (n.): "large cask," Old English tunne, a general North Sea Germanic word (cf. Old Frisian tunne, Middle Dutch tonne, Old High German tunna, German tonne), also found in Medieval Latin tunna (9c.) and Old French tonne, perhaps from a Celtic source (cf. Middle Irish, Gaelic tunna, Old Irish toun "hide, skin"). Tun-dish (late 14c.) was a funnel made to fit into the bung of a tun.
-- That? said Stephen. -- Is that called a funnel? Is it not a tundish? --
-- What is a tundish? --
--That. The ... the funnel. --
--Is that called a tundish in Ireland? -- asked the dean. -- I never heard the word in my life. --
-- It is called a tundish in Lower Drumcondra -- said Stephen, laughing -- where they speak the best English.--
-- A tundish -- said the dean reflectively. -- That is a most interesting word I must look that word up. Upon my word I must. --
His courtesy of manner rang a little false, and Stephen looked at the English convert with the same eyes as the elder brother in the parable may have turned on the prodigal. [Joyce, "Portrait of the Artist as a Young Man"]
tuna (n.): 1881, from American Spanish (California) tuna, from Spanish atun, from Arabic tun, from Latin thunnus "tunny" (see tunny).
tundra (n.): an Arctic steppe, 1841, from Russian tundra, from Lappish tundar "elevated wasteland."
tune (n.): late 14c., "a musical sound, a succession of musical notes," unexplained variant of tone. Meaning "state of being in proper pitch" is from mid-15c.
tune (v.): "bring into a state of proper pitch," c.1500, from tune (n.). Non-musical meaning "to adjust an organ or receiver" is recorded from 1887. Verbal phrase tune in in reference to radio (later also TV) is recorded from 1913; figurative sense of "become aware" is recorded from 1926. Tune out "to eliminate radio reception" is recorded from 1908; figurative sense of "disregard, stop heeding" is from 1928. Related: Tuned; tuning.
tune up (v.): "bring to a state of effectiveness," 1718, in reference to musical instruments, from tune (v.) + up. Attested from 1901 in reference to engines. Tune-up (n.) "event that serves as practice for a later one" is a U.S. sporting coinage first attested 1934.
tuner (n.): "device for varying the frequency of a radio or television," 1909, from tune.
tunesmith (n.): 1926, U.S. colloquial coinage, from tune (n.) + smith (n.).
tung: 1889, from Chinese tong.
tungsten (n.): rare metallic element, 1796, from Swedish tungsten "calcium tungstate," coined by its discoverer, Swedish chemist Karl Wilhelm Scheele (1742-1786) from tung "heavy" + sten "stone." Used earlier as the name for calcium tungstate (1770). Atomic symbol W is from Latin wolframium, from German Wolfram "iron tungstate" (see wolfram).
tunic (n.): c.1600, from Middle French tunique, from Latin tunica (cf. Spanish tunica, Italian tonica, Old English tunece, Old High German tunihha), probably from a Semitic source (cf. Hebrew kuttoneth "coat," Aramaic kittuna).
tunicate (adj.): 1760, from Latin tunicatus, past participle of tunicare "to clothe in a tunic," from tunica (see tunic). As a noun, from 1848.
tuning fork (n.): 1799, from gerundive of tune (v.) + fork (n.). Invented 1711 by John Shore.
tunnel (n.): mid-15c., "funnel-shaped net for catching birds," from Middle French tonnelle "net," or tonel "cask," diminutive of Old French tonne "tun, cask for liquids," possibly from the same source as Old English tunne (see tun).

Sense of "tube, pipe" (1540s) developed in English and led to sense of "underground passage," which is first attested 1765, about five years after the first modern tunnel was built (on the Grand Trunk Canal in England). This sense subsequently has been borrowed into French (1878). The earlier native word for this was mine. Meaning "burrow of an animal" is from 1873. Tunnel vision first recorded 1949. The figurative phrase light at the end of the tunnel is attested from 1922.
tunnel (v.): "excavate underground," 1795, from tunnel (n.).
tunny (n.): large sea-fish of the mackerel order, 1520s, probably from Middle French thon (14c.), from Old Provençal ton, from Latin thunnus "a tuna, tunny," from Greek thynnos "a tuna, tunny," possibly in the literal sense of "darter," from thynein "dart along."
tup (n.): "male sheep," c.1300, Scottish and Northern English; of unknown origin.
tupelo (n.): black gum tree, 1730, apparently from Cree (Algonquian) ito opilwa "swamp tree."
tuppence (n.): mid-15c., to-pens, representing the common pronunciation of twopence (see two + pence).
Tupperware (n.): 1956, trademark (reg. U.S.), from Earl S. Tupper, president of Tupper Corp., + ware. Patent claims use from 1950.
tuque (n.): 1871, from Canadian French variant of French toque (see toque).
turban (n.): 1560s, from Middle French turbant, from Italian turbante (Old Italian tolipante), from Turkish tülbent "gauze, muslin, tulle," from Persian dulband "turban." The change of -l- to -r- may have taken place in Portuguese India and thence been picked up in other European languages. A men's headdress in Muslim lands, it was popular in Europe and America c.1776-1800 as a ladies' fashion.
turbid (adj.): 1620s, from Latin turbidus "muddy, full of confusion," from turbare "to confuse, bewilder," from turba "turmoil, crowd," probably from Greek tyrbe "turmoil."