tropical (adj.) Look up tropical at Dictionary.com
1520s, "pertaining to the celestial tropics," from tropic + -al (1). In reference to the torrid zones of the earth, from 1690s. Meaning "hot and lush like the climate of the tropics" is first attested 1834.
tropism (n.) Look up tropism at Dictionary.com
1899, "tendency of an animal or plant to turn or move in response to a stimulus," 1899, abstracted from geotropism or heliotropism, with the second element taken in an absolute sense; ultimately from Greek tropos "a turning" (see trope).
troposphere (n.) Look up troposphere at Dictionary.com
1914, from French troposphère, literally "sphere of change," coined by French meteorologist Philippe Teisserenc de Bort (1855-1913) from Greek tropos "a turn, change" (see trope) + sphaira "sphere" (see sphere). Related: Tropopause.
trot (n.) Look up trot at Dictionary.com
"a gait faster than a walk and slower than a run," c.1300, originally of horses, from Old French trot "a trot, trotting" (12c.), from troter "to trot, to go," from Frankish *trotton, from Proto-Germanic *trott- (cognates: Old High German trotton "to tread"), derivative of *tred- (see tread (v.)). The trots "diarrhea" is recorded from 1808 (compare the runs).
trot (v.) Look up trot at Dictionary.com
"go at a quick, steady pace," late 14c., from Old French troter "to trot, to go," from Frankish *trotton (see trot (n.)). Italian trottare, Spanish trotar also are borrowed from Germanic. To trot (something) out originally (1838) was in reference to horses; figurative sense of "produce and display for admiration" is slang first recorded 1845. Related: Trotted; trotting.
troth (n.) Look up troth at Dictionary.com
"truth, verity," late 12c., from a phonetic variant of Old English treowð "faithfulness, veracity, truth" (see truth). Restricted to Midlands and Northern England dialect after 16c., and to certain archaic phrases (such as plight one's troth). Also see betroth.
Trotskyite (n.) Look up Trotskyite at Dictionary.com
1919, from Leon Trotsky, assumed name of Russian revolutionary leader Lev Davidovich Bronstein (1879-1940) + -ite (1).
trotter (n.) Look up trotter at Dictionary.com
late 14c. as a type of horse; agent noun from trot (v.). Meaning "foot of a quadruped" is from 1520s. Related: Trotters.
troubadour (n.) Look up troubadour at Dictionary.com
1727, from French troubadour (16c.) "one of a class of lyric poets in southern France, eastern Spain, and northern Italy 11c.-13c.," from Old Provençal trobador, from trobar "to find," earlier "invent a song, compose in verse," perhaps from Vulgar Latin *tropare "compose, sing," especially in the form of tropes, from Latin tropus "a song" (see trope). The alternative theory among French etymologists derives the Old Provençal word from a metathesis of Latin turbare "to disturb," via a sense of "to turn up." Meanwhile, Arabists posit an origin in Arabic taraba "to sing." General sense of "one who composes or sings verses or ballads" first recorded 1826.
trouble (v.) Look up trouble at Dictionary.com
c.1200, from Old French trubler, metathesis of turbler, torbler "to trouble, disturb; make cloudy, stir up, mix" (11c.), from Vulgar Latin *turbulare, from Late Latin turbidare "to trouble, make turbid," from Latin turbidus (see turbid). Related: Troubled; troubling.
trouble (n.) Look up trouble at Dictionary.com
c.1200, "agitation of the mind, emotional turmoil," from Old French truble, torble "trouble, disturbance" (12c.), from trubler/torbler (see trouble (v.)). From early 15c. as "a concern, a cause for worry;" 1590s as "something that causes trouble." Meaning "unpleasant relations with the authorities" is from 1550s. Related: Troubles (1510s). Trouble and strife as rhyming slang for "wife" is recorded from 1908.
troubled (adj.) Look up troubled at Dictionary.com
of persons, minds, etc., early 14c.; past participle adjective from trouble (v.). In reference to waters, etc., late 14c.
troublemaker (n.) Look up troublemaker at Dictionary.com
also trouble-maker, 1843, from trouble (n.) + maker.
troubleshoot (v.) Look up troubleshoot at Dictionary.com
also trouble-shoot, 1918 (implied in troubleshooting), probably a back-formation from troubleshooter.
troubleshooter (n.) Look up troubleshooter at Dictionary.com
also trouble-shooter, 1898, originally one who works on telegraph or telephone lines. From trouble (n.) + agent noun from shoot (v.).
troublesome (n.) Look up troublesome at Dictionary.com
1540s, from trouble (n.) + -some (1). Troublesomeness.
troublous (adj.) Look up troublous at Dictionary.com
early 15c., from Old French troblos, torblos, from truble/torble (see trouble (n.)).
trough (n.) Look up trough at Dictionary.com
Old English trog "wooden vessel, tray, hollow vessel, canoe," from Proto-Germanic *trugaz (cognates: Old Frisian, Old Saxon, Old Norse trog, Middle Dutch troch, Dutch trog, Old High German troc, German trog), from PIE *dru-ko-, from root *dru-, *deru- "wood, tree" (see tree (n.)). Originally pronounced in English with a hard -gh- (as in Scottish loch); pronunciation shifted to "-ff," but spelling remained.
trounce (v.) Look up trounce at Dictionary.com
1550s, "to trouble, afflict, harass," later "to beat, thrash" (1560s), of uncertain origin. Perhaps related to Middle French troncer "to cut, cut off a piece from," from tronce "piece of timber," from Old French tronc (see trunk). Related: Trounced; trouncing.
troupe (n.) Look up troupe at Dictionary.com
1825, "company, band," especially of performers, actors, dancers, etc., from French troupe "company" (see troop (n.)).
trouper (n.) Look up trouper at Dictionary.com
1890, "actor or performer in a troupe," from troupe (n.) + -er (1). Transferred sense of "reliable, uncomplaining person" [OED] is attested by 1942, American English.
trousers (n.) Look up trousers at Dictionary.com
"garment for men, covering the lower body and each leg separately," 1610s, earlier trouzes (1580s), extended from trouse (1570s), with plural ending typical of things in pairs, from Gaelic or Middle Irish triubhas "close-fitting shorts," of uncertain origin. Early recorded use of the word indicates the garment was regarded as Celtic: "A jellous wife was like an Irish trouze, alwayes close to a mans tayle" [1630]. The unexplained intrusive second -r- is perhaps by influence of drawers or other words in pairs ending in -ers.
trousseau (n.) Look up trousseau at Dictionary.com
"a bride's clothing, etc., brought from her former home," 1817, from French trousseau, originally "a bundle," diminutive of Old French trousse "bundle" (see truss (n.)). Italicized as foreign at first, nativized by 1833. The Old French word was borrowed into Middle English early 13c. as "a bundle of keys," but it fell from use.
trout (n.) Look up trout at Dictionary.com
Old English truht "trout," in part from Old French truite, both from Late Latin tructa, perhaps from Greek troktes "a kind of sea fish," literally "nibbler," from trogein "to gnaw," from PIE *tro-, from root *tere- (1) (see throw (v.)). In late 17c. slang, trusty trout was used in a sense of "confidential friend."
trove (n.) Look up trove at Dictionary.com
1888, from treasure trove (c.1550), from Anglo-French tresor trové (late 12c.), translating Latin thesaurus inventus, literally "treasure found." Originally any precious metal object one finds hidden whose owner is unknown. As this usually meant ancient hoards, the term came to mean "treasure hoard" in popular use. Rendered treasure found from mid-15c. French trove is past participle of trover "to find," from Old French trover, torver, of unknown origin, perhaps from Latin turbare "to move" (hence "to seek for") or Medieval Latin *tropare "to compose, sing."
trow (v.) Look up trow at Dictionary.com
Old English treowan "to trust in, believe, hope, be confident; persuade, suggest; make true; be faithful (to), confederate with," from treow "faith, belief," from Proto-Germanic *treuwaz- (cognates: Old Saxon truon, Old Frisian trouwa, Dutch vertrouwen "trust," Old High German triuwen, German trauen "hope, believe, trust;" see true (adj.)).
trowel (n.) Look up trowel at Dictionary.com
mid-14c., "tool for spreading plaster or mortar," from Old French truele "trowel" (13c.), from Late Latin truella "small ladle, dipper" (mid-12c.), diminutive of Latin trua "a stirring spoon, ladle, skimmer." The gardening tool was so called since 1796.
troy Look up troy at Dictionary.com
late 14c., standard system of weights for gems and precious metals, from Troyes, city in France (Roman (Civitas) Tricassium, capital of the Tricasses, a Celtic people whose name was said to mean "those with three tresses"), former site of an important fair at which this weight is said to have been used. Many medieval towns had their own standard weights. The pound troy contains 5,760 grains and is divided into 12 ounces.
truancy (n.) Look up truancy at Dictionary.com
1754, from truant + -cy.
truant (n.) Look up truant at Dictionary.com
c.1200, "beggar, vagabond," from Old French truant "beggar, rogue" (12c.), as an adjective, "wretched, miserable, of low caste," from Gaulish *trougant- (compare Breton *truan, later truant "vagabond," Welsh truan "wretch," Gaelic truaghan "wretched"), of uncertain origin. Compare Spanish truhan "buffoon," from same source. Meaning "one who wanders from an appointed place," especially "a child who stays away from school without leave" is first attested mid-15c.
truant (adj.) Look up truant at Dictionary.com
"idle, loitering, given to shirking duty or business," 1540s, from truant (n.).
truce (n.) Look up truce at Dictionary.com
"mutually agreed-upon temporary intermission of hostilities," early 13c., triws, variant of trewes, originally plural of trewe "faith, assurance of faith, covenant, treaty," from Old English treow "faith, truth, fidelity; pledge, promise, agreement, treaty," from Proto-Germanic *treuwaz- (cognates: Old Frisian triuwe, Middle Dutch trouwe, Dutch trouw, Old High German triuwa, German treue, Gothic triggwa "faith, faithfulness"). Related to Old English treowe "faithful" (see true (adj.)). The Germanic word was borrowed into Late Latin as tregua, hence French trève, Italian tregua.
trucial (adj.) Look up trucial at Dictionary.com
1876, from truce + -ial. Trucial States, the pre-1971 name of the United Arab Emirates, is attested from 1891, in reference to the 1835 maritime truce between Britain and the Arab sheiks of Oman.
truck (n.1) Look up truck at Dictionary.com
"vehicle," 1610s, originally "small wheel" (especially one on which the carriages of a ship's guns were mounted), probably from Latin trochus "iron hoop," from Greek trokhos "wheel," from trekhein "to run" (see truckle (n.)). Sense extended to "cart for carrying heavy loads" (1774), then in American English to "motor vehicle for carrying heavy loads" (1913), a shortened form of motor truck in this sense (1901).
There have also been lost to the enemy 6,200 guns, 2,550 tanks and 70,000 trucks, which is the American name for lorries, and which, I understand, has been adopted by the combined staffs in North-West Africa in exchange for the use of the word petrol in place of gasolene. [Winston Churchill, address to joint session of U.S. Congress, May 19, 1943]
Truck stop is attested from 1956.
truck (v.1) Look up truck at Dictionary.com
"to exchange, barter," early 13c., from Old North French troquer "to barter, exchange," from Medieval Latin trocare "barter," of unknown origin. Rare before 16c. Sense of "have dealings with" is first recorded 1610s. The noun is first recorded 1550s, "act or practice of barter." Sense of "vegetables raised for market" is from 1784, preserved in truck farm (1866).
truck (v.2) Look up truck at Dictionary.com
"to convey on a truck," 1809, from truck (n.). Verbal meaning "dance, move in a cool way," first attested 1935, from popular dance of that name in U.S., supposedly introduced at Cotton Club, 1933. Related: Trucked; trucking.
truck (n.2) Look up truck at Dictionary.com
1530s, "act or practice of barter, trading by exchange," from French troque, from troquer (see truck (v.1)). Sense of "dealings" is from 1620s. "Exchange of commodities, barter," then "commodities for barter and exchange." In this sense the word was given a wide use in 19c. American English: "Truck at first meant market-garden produce; then it came to mean stuff in general, including 'doctor-stuff.' SPUN TRUCK is knitting work" [Thornton, "American Glossary," 1912]. Sense of "vegetables raised for market" is from 1784, preserved in truck farm (1866).
trucker (n.) Look up trucker at Dictionary.com
1853, "worker who moves loads using a cart;" agent noun from truck (v.2). Meaning "person who drives a motorized truck" is by 1935, a shortening of truck driver (1907).
truckle (n.) Look up truckle at Dictionary.com
"small wheel or roller," late 14c., from Anglo-French trocle, from Latin trochlea "a small wheel, sheaf of a pulley," from Greek trokhileia "a system of pulleys," from trokhos "wheel," from trekhein "to run," from PIE root *dhregh- "to run" (cognates: Old Irish droch "wheel," Lithuanian pa-drosti "to run fast"). Truckle bed "small bed on wheels that can be stowed under a larger bed" is from mid-15c.
truckle (v.) Look up truckle at Dictionary.com
"give up or submit tamely," 1610s, originally "sleep in a truckle bed" (see truckle (n.)). Meaning "give precedence, assume a submissive position" (1650s, implied in truckling) is perhaps in reference to that type of bed being used by servants and inferiors or simply occupying the lower position. Related: Truckled; truckling.
truculence (n.) Look up truculence at Dictionary.com
1727, from Latin truculentia "savageness, cruelty," from truculentus (see truculent). Related: Truculency (1560s).
truculent (adj.) Look up truculent at Dictionary.com
1530s, from Latin truculentus "fierce, savage, stern, harsh, cruel," from trux (genitive trucis) "fierce, rough, savage, wild." Related: Truculently.
trudge (v.) Look up trudge at Dictionary.com
"to walk laboriously," 1540s, of unknown origin. Related: Trudged; trudging. The noun meaning "an act of trudging" is attested from 1835.
true (adj.) Look up true at Dictionary.com
Old English triewe (West Saxon), treowe (Mercian) "faithful, trustworthy, honest, steady in adhering to promises, friends, etc.," from Proto-Germanic *treuwaz- "having or characterized by good faith" (cognates: Old Frisian triuwi, Dutch getrouw, Old High German gatriuwu, German treu, Old Norse tryggr, Danish tryg, Gothic triggws "faithful, trusty"), from PIE *drew-o-, a suffixed form of the root *deru-/*dreu- "be firm, solid, steadfast" (cognates: Lithuanian drutas "firm," Welsh drud, Old Irish dron "strong," Welsh derw "true," Old Irish derb "sure"), with specialized sense "wood, tree" and derivatives referring to objects made of wood (see tree (n.)).

Sense of "consistent with fact" first recorded c.1200; that of "real, genuine, not counterfeit" is from late 14c.; that of "conformable to a certain standard" (as true north) is from c.1550. Of artifacts, "accurately fitted or shaped" it is recorded from late 15c. True-love (n.) is Old English treowlufu. True-born (adj.) first attested 1590s. True-false (adj.) as a type of test question is recorded from 1923. To come true (of dreams, etc.) is from 1819.
true (v.) Look up true at Dictionary.com
"make true in position, form, or adjustment," 1841, from true (adj.) in the sense "agreeing with a certain standard." Related: Trued; truing.
truffle (n.) Look up truffle at Dictionary.com
type of edible underground fungus, 1590s, from Middle French trufle (14c.), probably from Old Provençal trufa, metathesized from Late Latin tufera (plural), cognate of Latin tuber "edible root." Another theory notes Italian tartuffo (Milanese tartuffel) "potato," supposedly from terræ tuber. Extended 1926 to powdered, round chocolates that look like truffles.
truism (n.) Look up truism at Dictionary.com
"self-evident truth," 1708, from true (adj.) + -ism; first attested in Swift.
trull (n.) Look up trull at Dictionary.com
"a low prostitute or concubine; a drab, strumpet, trollop" [OED], 1510s, from German trulle "trollop, wench, hussy," perhaps cognate with troll (n.), or perhaps from troll (v.), compare Middle High German trolle "awkward fellow," Swabian trull "a thick, fat woman."
truly (adv.) Look up truly at Dictionary.com
Old English treowlice, from treow (see true (adj.)). Similar formation in Dutch treuwelijk, German getreulich, Swedish troligen.
Truman Look up Truman at Dictionary.com
surname, attested by 1215, literally "faithful man, trusty man."