treatable (adj.) Look up treatable at Dictionary.com
c.1300, "amenable to reason," from Anglo-French tretable, Old French traitable, and in part from treat (v.) + -able. Of wounds, diseases, etc., "receptive to treatment," early 15c.
treatise (n.) Look up treatise at Dictionary.com
early 14c., from Anglo-French tretiz (mid-13c.), contracted from Old French traitis "treatise, account," from traitier "deal with; set forth in speech or writing" (see treat (v.)).
treatment (n.) Look up treatment at Dictionary.com
1560s, "conduct or behavior toward someone or something," from treat (v.) + -ment. In the medical sense, it is first recorded 1744.
treaty (n.) Look up treaty at Dictionary.com
late 14c., "treatment, discussion," from Anglo-French treté, Old French traitié "assembly, agreement, dealings," from Latin tractatus "discussion, handling, management," from tractare "to handle, manage" (see treat (v.)). Sense of "contract or league between nations or sovereigns" is first recorded early 15c.
treble (adj.) Look up treble at Dictionary.com
"three times, triple," c.1300, from Old French treble (12c.), from Latin triplus "threefold" (see triple). Related: Trebly.
treble (v.) Look up treble at Dictionary.com
"to multiply by three," early 14c., from Old French trebler, from treble "triple" (see treble (adj.)). Related: Trebled; trebling.
treble (n.) Look up treble at Dictionary.com
"highest part in music, soprano," mid-14c., from Anglo-French treble, Old French treble "a third part," noun use of adjective (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.) Look up trebuchet at Dictionary.com
"medieval stone-throwing engine of war," c.1300 (in Anglo-Latin from early 13c.), from Old French trebuchet (12c.) "stone-throwing siege engine," from trabuchier "to overturn, fall to the ground, overthrow" (11c.), from tra- (from Latin trans-, here expressing "displacement") + Old French buc "trunk, bulk," from Frankish *buk- "trunk of the body," from Proto-Germanic *bheu-, variant of *beu-, used in forming words loosely associated with swelling (such as German bauch "belly;" see bull (n.2)).
tree (n.) Look up tree at Dictionary.com
Old English treo, treow "tree" (also "timber, wood, beam, log, stake"), from Proto-Germanic *treuwaz- (cognates: Old Frisian tre, Old Saxon trio, Old Norse tre, Gothic triu "tree"), from PIE *drew-o-, from *deru- "oak" (cognates: Sanskrit dru "tree, wood," daru "wood, log;" Greek drys "oak," drymos "copse, thicket," doru "beam, shaft of a 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"). This is from PIE *drew-o-, a suffixed form of the root *deru- "to be firm, solid, steadfast" (see true), with specialized sense "wood, tree" and derivatives referring to objects made of wood.
The line which divides trees from shrubs is largely arbitrary, and dependent upon habit rather than size, the tree having a single trunk usually unbranched for some distance above the ground, while a shrub has usually several stems from the same root and each without a proper trunk. [Century Dictionary]
The widespread use of words originally meaning "oak" in the sense "tree" probably reflects the importance of the oak to ancient Indo-Europeans. In Old English and Middle English also "thing made of wood," especially the cross of the Crucifixion and a gallows (such as Tyburn tree, famous gallows outside London). Middle English also had plural treen, adjective treen (Old English treowen "of a tree, wooden"). For Dutch boom, German Baum, the usual words for "tree," see beam (n.). Meaning "framework of a saddle" is from 1530s. Meaning "representation of familial relationships in the form of a tree" is from c.1300. 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]
tree (v.) Look up tree at Dictionary.com
"to chase up a tree," 1700, from tree (n.). Meaning "take a tree-like form" is from 1884. Related: Treed; treeing.
tree-frog (n.) Look up tree-frog at Dictionary.com
1738, from tree (n.) + frog (n.1).
tree-house (n.) Look up tree-house at Dictionary.com
1867, from tree (n.) + house (n.).
tree-top (n.) Look up tree-top at Dictionary.com
1520s, from tree (n.) + top (n.).
treeless (adj.) Look up treeless at Dictionary.com
1742, from tree (n.) + -less.
tref (n.) Look up tref at Dictionary.com
Welsh, literally "hamlet, home, town," from PIE *treb- "dwelling" (see tavern).
trefoil (n.) Look up trefoil at Dictionary.com
late 14c., type of clover, from Anglo-French trifoil (13c.), Old French trefueil "clover, clover-leaf," from Latin trifolium "three-leaved plant," from tri- "three" (see tri-) + folium "leaf" (see folio). As a type of ornamental figure in medieval architecture, early 15c.
trek Look up trek at Dictionary.com
1849 (n.) "a stage of a journey by ox wagon;" 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 (cognate with 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, discontented with the English colonial authorities, left Cape Colony and went north and north-east. In general use as a noun by 1941. Related: Trekked; trekking.
trekker (n.) Look up trekker at Dictionary.com
"one who treks," 1851, agent noun from trek (v.).
trekkie (n.) Look up trekkie at Dictionary.com
1888, South African, "party of trekkers" (see trek). Meaning "fan of the television program 'Star Trek' " attested by 1976.
trellis (n.) Look up trellis at Dictionary.com
late 14c., "lattice, grating," from Old French trelis, trellis "trellis, fence," originally "sackcloth," from Vulgar Latin *trilicius, from Latin trilicis, genitive of trilix "having three threads, triple-twilled," from tri- (see tri-) + licium "thread."

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. As a verb, c.1400. Related: Trellised.
tremble (v.) Look up tremble at Dictionary.com
c.1300, "shake from fear, cold, etc.," from Old French trembler "tremble, fear" (11c.), from Vulgar Latin *tremulare (source also of Italian tremolare, Spanish temblar), from Latin tremulus "trembling, shaking, quaking," from tremere "to tremble, shiver, quake," from PIE *trem- "to tremble" (cognates: Greek tremein "to shiver, tremble, to quake, to fear," 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.) Look up tremblor at Dictionary.com
"earthquake," 1913, alteration of temblor, by influence of trembler, agent noun of tremble (v.).
tremendous (adj.) Look up tremendous at Dictionary.com
1630s, "awful, dreadful, terrible," from Latin tremendus "fearful, to be dreaded, terrible," literally "to be trembled at," gerundive form of tremere "to tremble" (see tremble (v.)). Hyperbolic or intensive sense of "extraordinarily great or good, immense" is attested from 1812, paralleling semantic changes in terrific, terrible, dreadful, awful, etc. Related: Tremendously.
tremolo (n.) Look up tremolo at Dictionary.com
"tremulous effect in music," 1801, from Italian tremolo, from Latin tremulus "trembling" (see tremulous).
tremor (n.) Look up tremor at Dictionary.com
late 14c., "terror," from Old French tremor "fear, terror, quaking" (13c.), from Latin tremorem (nominative tremor) "a trembling, terror," from tremere (see tremble (v.)). Sense of "an involuntary shaking" first recorded 1610s and probably represents a re-introduction from Latin.
tremulous (adj.) Look up tremulous at Dictionary.com
1610s, from Latin tremulus "shaking, quivering," from tremere "to shake, quake, quiver" (see tremble (v.)). Related: Tremulously; tremulousness.
trench (n.) Look up trench at Dictionary.com
late 14c., "track cut through a wood," later "long, narrow ditch" (late 15c.), from Old French trenche "a slice, cut, gash, slash; defensive ditch" (13c., Modern French tranche), from trenchier "to cut, carve, slice," possibly from Vulgar Latin *trincare, from Latin truncare "to cut or lop off" (see truncate). Trenches for military protection are first so called c.1500. Trench warfare first attested 1918. Trench-coat first recorded 1916, a type of coat worn by British officers in the trenches during World War I.
trenchant (adj.) Look up trenchant at Dictionary.com
early 14c., "cutting, sharp," from Old French trenchant "cutting, sharp" (literal and figurative), present participle of trenchier "to cut" (see trench). Figurative sense in English is from c.1600.
trencher (n.) Look up trencher at Dictionary.com
"wooden platter on which to cut meat," c.1300, from Anglo-French trenchour, Old North French trencheor "a trencher," literally "a cutting place," from Old French trenchier "to cut, carve, slice" (see trench).
trend (v.) Look up trend at Dictionary.com
1590s, "to run or bend in a certain direction" (of rivers, coasts, etc.), from Middle English trenden "to roll about, turn, revolve," from Old English trendan "turn round, revolve, roll," from Proto-Germanic *trandijan (cognates: Old English trinde "round lump, ball," Old Frisian trind, Middle Low German trint "round," Middle Low German trent "ring, boundary," Dutch trent "circumference," Danish trind "round"); origin and connections outside Germanic uncertain. Sense of "have a general tendency" (used of events, opinions, etc.) is first recorded 1863, from the nautical sense. Related: Trended; trending.
trend (n.) Look up trend at Dictionary.com
"the way something bends" (coastline, mountain range, etc.), 1777, earlier "round bend of a stream" (1620s), from trend (v.); sense of "general course or direction" is from 1884. Sense of "a prevailing new tendency in popular fashion or culture" is from c.1950.
trendsetter (n.) Look up trendsetter at Dictionary.com
also trend-setter, 1950, from trend (n.) + agent noun from set (v.). Related: Trend-setting.
trendy (adj.) Look up trendy at Dictionary.com
1962, from trend (n.) + -y (2). Related: Trendily; trendiness.
Trent Look up Trent at Dictionary.com
river in England, a Celtic name, perhaps "great wanderer," in reference to its flooding. The city in Italy (Italian Trento) is Roman Tridentum, in reference to the triple-peaked mountain nearby. The great ecumenical council there was held from 1543-63.
Trenton Look up Trenton at Dictionary.com
city in New Jersey, U.S., originally Trent’s Town, from William Trent, Philadelphia merchant who laid it out in 1714.
trepan (v.) Look up trepan at Dictionary.com
c.1400, from Old French trépaner (14c.), from trepan (n.), the name of the tool with which it was done, from Medieval Latin trepanum "a saw for cutting out small pieces of bone from the skull," from Greek trypanon "a borer, an auger, a carpenter's tool; a surgeon's trepan," from trypan "to bore," related to trype "hole" (cognate with Old Church Slavonic truplu "hollow"), from PIE *trup-, from root *tere- (1) "to rub, turn" (see throw (v.)). Related: Trepanned; trepanning.
trephine (n.) Look up trephine at Dictionary.com
an improved kind of trepan, 1620s, from French trephine, which is said to be from Latin tres fines "three ends," but perhaps rather an arbitrary diminutive of trepan. As a verb from 1804. Related: Trephining; trephination.
trepid (adj.) Look up trepid at Dictionary.com
"trembling from fear or terror," 1640s, from Latin trepidus "scared" (see trepidation). Related: Trepidly; trepidness.
trepidation (n.) Look up trepidation at Dictionary.com
c.1600, from Middle French trepidation (15c.) and directly from Latin trepidationem (nominative trepidatio) "agitation, alarm, trembling," noun of action from past participle stem of trepidare "to tremble, hurry," from trepidus "alarmed, scared," from PIE *trep- (1) "to shake, tremble" (cognates: Sanskrit trprah "hasty," Old Church Slavonic trepetati "to tremble"), related to *trem- (see tremble (v.)).
tres (adv.) Look up tres at Dictionary.com
"very," 1815, from French très, from Old French tres "right, precisely, completely, very," from Latin trans "beyond" (see trans-), later "very" (compare Old Italian trafreddo "very cold").
trespass (v.) Look up trespass at Dictionary.com
c.1300, "transgress in some active manner, commit an aggressive offense, to sin," from Old French trespasser "pass beyond or across, cross, traverse; infringe, violate," from tres- "beyond" (from Latin trans-; see trans-) + passer "go by, pass" (see pass (v.)). Meaning "enter unlawfully" is first attested in forest laws of Scottish Parliament (c.1455). The Modern French descendant of Old French trespasser, trépasser, has come to be used euphemistically for "to die" (compare euphemistic use of cross over, and obituary). Related: Trespassed; trespassing.
trespass (n.) Look up trespass at Dictionary.com
c.1300, "a transgression," from Old French trespas, verbal noun from trespasser (see trespass (v.)). Related: Trespasses.
tress (n.) Look up tress at Dictionary.com
c.1300, "long lock of hair," from Old French tresse "a plait or braid of hair" (12c.), of uncertain origin, perhaps from Vulgar Latin *trichia "braid, rope," from Greek trikhia "rope," from thrix (genitive trikhos) "hair." Related: Tresses.
tress (v.) Look up tress at Dictionary.com
"arrange in tresses," mid-14c., from Old French trecier (12c.), from tresse (see tress (n.)).
tressel (n.) Look up tressel at Dictionary.com
see trestle.
trestle (n.) Look up trestle at Dictionary.com
early 14c., "a support for something," from Old French trestel "crossbeam" (12c., Modern French tréteu), presumed to be an alteration of Vulgar Latin *transtellum, diminutive of transtrum "beam, crossbar" (see transom). Specific meaning "support for a bridge" is recorded from 1796.
tret (n.) Look up tret at Dictionary.com
"allowance on goods sold by weight," c.1500, of unknown origin; perhaps related to trait "act of drawing."
Trevor Look up Trevor at Dictionary.com
surname, from Trevor, Denbeigh.
trey (n.) Look up trey at Dictionary.com
late 14c., "card, die, or domino with three spots," from Anglo-French, Old French treis (Modern French trois), oblique case of treie "three," from Latin tria (neuter) "three" (see three). In slang use for "three (of anything)" from 1887.
tri- Look up tri- at Dictionary.com
word-forming element meaning "three, having three, once every three," from Latin tres (neuter tria) or Greek treis, trias "three" (see three).