Online Etymology Dictionary

traumatise (v.): chiefly British English spelling of traumatize; for suffix, see -ize. Related: Traumatised; traumatising.
traumatize (v.): 1903, of physical wounds; 1949 in the psychological sense, from Greek traumat-, stem of trauma (see trauma).
travail (n.): "labor, toil," mid-13c., from Old French travail "suffering or painful effort, trouble" (12c.), from travailler "to toil, labor," originally "to trouble, torture," from Vulgar Latin *tripaliare "to torture," from *tripalium (in Late Latin trepalium) "instrument of torture," probably from Latin tripalis "having three stakes" (from tria, tres "three" + palus "stake"), which sounds ominous, but the exact notion is obscure. The verb is recorded from late 13c.
trave (n.): late 14c., from Old French trave "beam," from Latin trabem (nominative trabs) "beam."
travel (v.): late 14c., "to journey," from travailen (1300) "to make a journey," originally "to toil, labor" (see travail). The semantic development may have been via the notion of "go on a difficult journey," but it may also reflect the difficulty of going anywhere in the Middle Ages. Replaced Old English faran. Travels "accounts of journeys" is recorded from 1590s. Traveled "experienced in travel" is from early 15c. Traveling salesman is attested from 1885.
traveler (n.): also traveller, late 14c., agent noun from travel (v.).
travelogue (n.): "a talk on travel," 1903, a hybrid word coined by U.S. traveler Burton Holmes (1870-1958) from travel + Greek-derived -logue, abstracted from monologue.
traverse (v.): early 14c., "pass across, over, or through," from Old French traverser "to cross, thwart" (11c.), from Vulgar Latin *traversare, from Latin transversare "to cross, throw across," from Latin transversus "turn across" (see transverse). The noun meaning "act of passing through a gate, crossing a bridge, etc." is recorded from mid-14c.; meaning "a passage by which one may traverse" is recorded from 1670s. Military foritifcation sense of "barrier, barricade" is recorded from 1590s. Related: Traversed; traversing.
travertine (n.): 1797, from Italian travertino "a kind of building stone," from Latin tiburtinus, from Tiburs, adjective from Tibur (modern Tivoli), region in Latium.
travesty (n.): 1670s, from adjective meaning "dressed so as to be made ridiculous, parodied, burlesqued" (c.1660s), from French travesti "dressed in disguise," past participle of travestir "to disguise" (1590s), from Italian travestire "to disguise," from Latin trans- "over" (see trans-) + vestire "to clothe" (see wear (v.)).
Traviata, La: title of an opera by Verdi, from Italian, literally "the woman led astray," from traviata literally "to lead beyond the way," from tra- "across, beyond" (from Latin trans-; see trans-) + via "way" (see via).
Travis: masc. proper name, also a surname (late 12c.), from an Old French word meaning "to cross over," related to traverse. Probably a name for a gatekeeper or the toll collector of a bridge.
travois (n.): 1847, said to be ultimately from a Canadian Indian pronunciation of travail.
trawl (v.): 1560s, from Dutch tragelen, from Middle Dutch traghelen "to drag," from traghel "dragnet," probably from Latin tragula "dragnet." Related: Trawled; trawling.
trawler (n.): 1590s, agent noun from trawl.
tray (n.): Old English treg, trig "flat board with a low rim," from Proto-Germanic *traujan (cf. Old Swedish tro, a corn measure). Related to Old English treow "wood, tree" (see tree (n.)) and the primary sense may have been "wooden vessel."
treacherous (adj.): early 14c., from Old French trecheros (12c.), from trecheur, agent noun from trechier "to cheat, trick" (see trick). Figuratively, of things, from c.1600. Related: Treacherously; treacherousness.
treachery (n.): early 13c., from Old French trecherie "deceit, cheating" (12c.), from trechier "to cheat, deceive" (see trick).
treacle (n.): mid-14c., "medicinal compound, antidote for poison," from Old French triacle "antidote" (c.1200), from Vulgar Latin *triacula, from Latin theriaca, from Greek theriake (antidotos) "antidote for poisonous wild animals," from fem. of theriakos "of a wild animal," from therion "wild animal," diminutive of ther (genitive theros) "wild animal," from PIE root *ghwer- "wild" (see fierce).

Sense of "molasses" is first recorded 1690s; that of "anything too sweet or sentimental" is from 1771. The connection may be from the use of molasses as a laxative, or its use to disguise the bad taste of medicine.
tread (v.): Old English tredan (class V strong verb; past tense træd, past participle treden), from Proto-Germanic *tredanan (cf. Old Frisian treda, Middle Dutch treden, Old High German tretan, German treten, Gothic trudan, Old Norse troða).
tread (n.): early 13c., from tread (v.); in reference to automobile tires, it is recorded from 1906.
treadle (n.): "lever worked by foot," c.1400, from Old English tredel "step, stair," from tredan "to tread" (see tread) + instrumental suffix -el (cf. handle).
treadmill (n.): invented (and named) 1822 by William Cubitt of Ipswich, England; originally an instrument of prison discipline; from tread (v.) + mill (n.1).
treason (n.): early 13c., from Anglo-French treson, from Old French traison (11c.; Modern French trahison), from Latin traditionem (nominative traditio) "a handing over, delivery, surrender" (see tradition). Old French form influenced by the verb trair "betray." In old English law, high treason is violation by a subject of his allegiance to his sovereign or to the state; distinguished from petit treason, treason against a subject, such as murder of a master by his servant.
treasonous (adj.): mid-15c., from treason + -ous. Related: Treasonously.
treasure (n.): mid-12c., from Old French tresor "treasury, treasure" (11c.), from Gallo-Romance *tresaurus, from Latin thesaurus "treasury, treasure" (cf. Spanish, Italian tesoro), from Greek thesauros "store, treasure, treasure house" (see thesaurus). Replaced Old English goldhord. General sense of "anything valued" is recorded from c.1200. Treasure hunt is first recorded 1913. For treasure trove, see trove.
treasure (v.): late 14c., "to amass treasure; to store up for the future," also figurative, from treasure (n.). Related: Treasured; treasuring.
treasurer (n.): late 13c., from Old French tresorier, from tresor (see treasure (n.)).
treasury (n.): late 13c., "room for treasure," from Old French tresorie (11c.), from tresor (see treasure). Meaning "department of state that controls public revenue" is recorded from late 14c. An Old English word for "room for treasure" was maðm-hus.
treat (v.): c.1300, "negotiate, bargain, deal with," from Old French traiter (12c.), from Latin tractare "manage, handle, deal with," originally "drag about," frequentative of trahere (past participle tractus) "to pull, draw" (see tract (n.1)). Meaning "to entertain with food and drink by way of compliment or kindness (or bribery)" is recorded from c.1500. Sense of "deal with in speech or writing" (early 14c.) led to the use in medicine (1781), "to attempt to heal or cure." Related: Treated; treating.
treat (n.): late 14c., "action of discussing terms," from treat (v.). Sense of "a treating with food and drink" (1650s) was extended by 1770 to "anything that gives pleasure."
treatise (n.): c.1300, from Anglo-French tretiz (mid-13c.), contracted from Old French traiteiz, from Gallo-Romance *tractaticius, from Latin tractare "to deal with" (see treat).
treatment (n.): "conduct, behavior," 1560s, from treat + -ment. In the medical sense, it is first recorded 1744.
treaty (n.): late 14c., "treatment, discussion," from Old French traité "assembly, agreement, treaty," from Latin tractatus "discussion, handling," from tractare "to handle, manage" (see treat). Sense of "contract between nations" is first recorded early 15c.
treble (adj.): late 14c., "three times, triple," from Old French treble (12c.), from Latin triplus (see triple).
treble (v.): early 14c., "to multiply by three," from Old French trebler, from treble (see treble (adj.)). Related: Trebled; trebling.
treble (n.): "highest part in music, soprano," mid-14c., from Anglo-French treble, Old French treble (see treble (adj.)). In early contrapuntal music, the chief melody was in the tenor, and the treble was the "third" part above it (after the alto).
trebuchet (n.): "medieval stone-throwing engine of war," c.1300 (in Anglo-Latin from early 13c.), from Old French trebuchet (12c.) "siege engine," from trabucher "to overturn, overthrow" (11c.), from tra- (from Latin trans-, here expressing "displacement") + Old French buc "trunk, bulk," from West Germanic *buh- (cf. German bauch "belly").
tree (n.): Old English treo, treow "tree" (also "wood"), from Proto-Germanic *trewan (cf. Old Frisian tre, Old Saxon trio, Old Norse tre, Gothic triu), from PIE *deru- "oak" (cf. Sanskrit dru "tree, wood," daru "wood, log;" Greek drys "oak," doru "spear;" Old Church Slavonic drievo "tree, wood;" Serbian drvo "tree," drva "wood;" Russian drevo "tree, wood;" Czech drva; Polish drwa "wood;" Lithuanian derva "pine wood;" Old Irish daur, Welsh derwen "oak," Albanian drusk "oak").

Importance of the oak in mythology is reflected in the recurring use of words for "oak" to mean "tree." In Old English and Middle English, also "thing made of wood," especially the cross of the Crucifixion and a gallows (cf. Tyburn tree, gallows mentioned 12c. at Tyburn, at junction of Oxford Street and Edgware Road, place of public execution for Middlesex until 1783). Sense in family tree first attested 1706; verb meaning "to chase up a tree" is from 1700. Tree-hugger, contemptuous for "environmentalist" is attested by 1989.
Minc'd Pyes do not grow upon every tree,
But search the Ovens for them, and there they be.
["Poor Robin," Almanack, 1669]
tref (n.): Welsh, literally "hamlet, home, town."
trefoil (n.): c.1400, from Anglo-French trifoil (c.1265), from Old French trefeuil, from Latin trifolium "three-leaved plant," from tri- "three" (see tri-) + folium "leaf" (see folio).
trek: 1849 (n.); 1850 (v.), "to travel or migrate by ox wagon," from Afrikaans trek, from Dutch trekken "to march, journey," originally "to draw, pull," from Middle Dutch trecken (cf. Middle Low German trecken, Old High German trechan "to draw"). Especially in reference to the Groot Trek (1835 and after) of more than 10,000 Boers, who, discontent with the English colonial authorities, left Cape Colony and went north and north-east.
trekker (n.): 1851, agent noun from trek (v.).
trekkie (n.): 1888, South African, "party of trekkers" (see trek). Meaning "fan of the television program 'Star Trek' " attested by 1976.
trellis (n.): c.1400, "lattice, grating," from Old French trelis, originally "sackcloth," from Vulgar Latin *trilicius, from Latin trilicis, genitive of trilix "having three threads, triple-twilled," from tri- three + licium "thread." Cognate with Greek trimitos. Sense extended in Old French to things "woven" of iron, etc., which brought on influence of Old French treille "vine trellis," perhaps from Latin trichila "bower, arbor," which is apparently from Latin triclinium "couch extending round three sides of a table" (for reclining on at meals). Meaning "lattice used to support growing vines" is from 1510s.
tremble (v.): c.1300, "shake from fear, cold, etc.," from Old French trembler "tremble, fear" (11c.), from Vulgar Latin *tremulare (source of Italian tremolare, Spanish temblar), from Latin tremulus "trembling, tremulous," from tremere "to tremble, shiver, quake," from PIE *trem- "to tremble" (cf. Greek tremein "to shiver, tremble," Lithuanian trimu "to chase away," Old Church Slavonic treso "to shake," Gothic þramstei "grasshopper"). A native word for this was Old English bifian. Related: Trembled; trembling. The noun is recorded from c.1600.
tremblor (n.): "earthquake," 1913, alteration of temblor, by influence of trembler.
tremendous (adj.): 1630s, "awful, dreadful, terrible," from Latin tremendus "fearful, terrible," literally "to be trembled at," gerundive form of tremere "to tremble" (see tremble). Hyperbolic or intensive sense of "extraordinarily great or good, immense" is attested from 1812, paralleling semantic changes in terrific, terribly, awfully, etc.
tremolo: 1801, from Italian tremolo, from Latin tremulus "trembling" (see tremulous).
tremor (n.): late 14c., "terror," from Old French tremor "fear, terror" (13c.), from Latin tremorem (nominative tremor) "a trembling, terror," from tremere (see tremble). Sense of "an involuntary shaking" first recorded 1610s and probably represents a re-introduction from Latin.