Online Etymology Dictionary

trail (v.): c. 1300, "to hang down loosely and flow behind" (of a gown, sleeve, etc.), from Old French trailler "to tow; pick up the scent of a quarry," ultimately from Vulgar Latin *tragulare "to drag," from Latin tragula "dragnet, javelin thrown by a strap," probably related to trahere "to pull" (see tract (n.1)). Transitive sense of "to tow or pull along the ground" is from c. 1400. The meaning "follow the trail of" (an animal, etc.) is first recorded late 14c. Meaning "to lag behind" is from 1957. Related: Trailed; trailing.
trail (n.): early 14c., "trailing part of a robe, gown, etc.," from trail (v.). The meaning "track or smell left by a person or animal" is also from 1580s. Meaning "path or track worn in wilderness" is attested from 1807. Trail of Tears in reference to the U.S. government's brutally incompetent Cherokee removal of 1838-9 is attested by 1908.
trailblazer (n.): by 1893, from trail (n.) + agent noun from blaze (v.3).
trailer (n.): 1580s, "hound or huntsman that follows a trail," agent noun from trail (v.). From 1610s as "Something that trails." From 1890 as "vehicle pulled by another;" originally a small carriage drawn along by a bicycle. Meaning "preview of a coming movie" first attested 1928. Trailer park "mobile home community" recorded by 1936. Trailer trash in use by 1986.
train (n.): early 14c., "a drawing out, delay;" late 14c., "trailing part of a skirt, gown, or cloak;" also "retinue, procession," from Old French train "tracks, path, trail (of a rome or gown); act of dragging," from trainer "to pull, drag, draw," from Vulgar Latin *traginare, extended from *tragere "to pull," back-formation from tractus, past participle of Latin trahere "to pull, draw" (see tract (n.1)).,

General sense of "series, progression, succession, continuous course" is from late 15c. Train of thought first attested 1650s. The railroad sense "locomotive and the cars coupled to it" is recorded from 1820 (publication year, dated 1816), from notion of a "train" of wagons or carriages pulled by a mechanical engine.
train (v.): "to discipline, teach, bring to a desired state by means of instruction," 1540s, probably from earlier sense of "draw out and manipulate in order to bring to a desired form" (late 14c.), specifically of the growth of branches, vines, etc. from mid-15c.; from train (n.). Sense of "point or aim" (a firearm, etc.) is from 1841. Sense of "fit oneself for a performance by a regimen or exercise" is from 1832. The meaning "to travel by railway" is recorded from 1856. Related: Trained; training.
train-spotting (n.): 1959 (train spotter attested from 1958), chiefly British English, in reference to the hobby of recording the numbers of railway locomotives one has observed; from train (n.) in the railroad sense + verbal noun from spot (v.).
trainable (adj.): 1540s, from train (v.) + -able.
trainee (n.): 1841, from train (v.) in the "instruct" sense + -ee.
trainer (n.): c. 1600, "one who educates or instructs," agent noun from train (v.). Meaning "one who prepares another for feats requiring physical fitness" is from 1823, originally of horse-trainers.
training (n.): mid-15c., "protraction, delay," verbal noun from train (v.). From 1540s as "discipline and instruction to develop powers or skills;" 1786 as "exercise to improve bodily vigor." Training wheels as an attachment to a bicycle is from 1953.
Training is the development of the mind or character or both, or some faculty, at some length, by exercise, as a soldier is trained or drilled. Discipline is essentially the same as training, but more severe. [Century Dictionary]
traipse (v.): 1590s, of uncertain origin, perhaps from dialectal French trepasser "pass over or beyond," from Old French trespasser "cross, traverse, transgress" (see trespass). Or from a source related to Middle Dutch trappen, dialectal Norwegian trappa "to tread, stamp" (see trap (n.)). Liberman points out that it resembles German traben "tramp" "and other similar verbs meaning 'tramp; wander; flee' in several European languages. They seem to have been part of soldiers' and vagabonds' slang between 1400 and 1700. In all likelihood, they originated as onomatopoeias and spread to neighboring languages from Low German." Related: Traipsed; traipsing.
trait (n.): late 15c., "shot, missiles;" later "a stroke in drawing, a short line" (1580s), from Middle French trait "line, stroke, feature, tract," from Latin tractus "drawing, drawing out, dragging, pulling," later "line drawn, feature," from past participle stem of trahere "to pull, draw" (see tract (n.1)). Sense of "particular feature, distinguishing quality" in English is first recorded 1752.
traitor (n.): c. 1200, "one who betrays a trust or duty," from Old French traitor, traitre "traitor, villain, deceiver" (11c., Modern French traître), from Latin traditor "betrayer," literally "one who delivers," agent noun from stem of tradere "deliver, surrender" (see tradition). Originally usually with a suggestion of Judas Iscariot; especially of one false to his allegiance to a sovereign, government, or cause from late 15c.
traitorous (adj.): late 14c., "guilty of treason," apparently from Old French traitros "treacherous" (13c.), from traitor (see traitor). Related: Traitorously; traitorousness.
trajectory (n.): "path described by a body moving under the influence of given forces," 1690s, from Modern Latin trajectorium, from trajectorius "of or pertaining to throwing across," from Latin traiectus "thrown over or across," past participle of traicere "throw across, shoot across," from Latin trans- "across" (see trans-) + icere, combining form of iacere "to throw" (see jet (v.)). Middle French and Middle English had trajectorie as "end of a funnel," from Latin traiectorium.
tram (n.): c. 1500, "beam or shaft of a barrow or sledge," also "a barrow or truck body" (1510s), Scottish, originally in reference to the iron trucks used in coal mines, probably from Middle Flemish tram "beam, handle of a barrow, bar, rung," a North Sea Germanic word of unknown origin. The sense of "track for a barrow, tramway" is first recorded 1826; that of "streetcar" is first recorded 1879, short for tram-car "car used on a tramway" (1873).
trammel (n.): mid-14c., "net to catch fish" (implied in trammeller "one who fishes with a trammel net"), from Old French tramail "fine-gauged fishnet" (13c.), from Late Latin tremaculum, perhaps meaning "a net made from three layers of meshes," from Latin tri- "three" (see tri-) + macula "a mesh" (see mail (n.2)). Meaning "anything that hinders" is from 1650s, originally "a hobble for a horse" (c. 1500). Italian tramaglio, Spanish trasmallo are French loan-words.
trammel (v.): 1530s, originally "to bind up (a corpse);" sense of "hinder, restrain" is from 1727, from trammel (n.), a figurative use from the literal sense "bind (a horse's legs) with a trammel" (c. 1600). Related: Trammeled; trammeling.
tramp (v.): late 14c., "walk heavily, stamp," from Middle Low German trampen "to stamp," from Proto-Germanic *tremp- (source also of Danish trampe, Swedish trampa "to tramp, stamp," Gothic ana-trimpan "to press upon"), from PIE *der- (1) "to run, walk, step" (see tread (v.)). Related: Tramped; tramping.
tramp (n.): "person who wanders about, idle vagrant, vagabond," 1660s, from tramp (v). Sense of "steamship which takes cargo wherever it can be traded" (as opposed to one running a regular line) is attested from c. 1880. The meaning "promiscuous woman" is from 1922. Sense of "a long, toilsome walk" is from 1786.
trample (v.): late 14c., "to walk heavily," frequentative form of tramp (v.) + -el (3). Transitive sense "beat down by continuously treading on" is from mid-15c. Related: Trampled; trampling. As a noun from c. 1600.
trampoline (n.): 1798, from Spanish trampolin "springboard," and Italian trampolino, from trampoli "stilts," from a Germanic source (compare Low German trampeln "trample") related to tramp (v.).
trance (n.): late 14c., "state of extreme dread or suspense," also "a half-conscious or insensible condition, state of insensibility to mundane things," from Old French transe "fear of coming evil," originally "coma, passage from life to death" (12c.), from transir "be numb with fear," originally "die, pass on," from Latin transire "cross over" (see transient). French trance in its modern sense has been reborrowed from English. As a music genre, from c. 1993.
tranche (n.): c. 1500, from French tranche "a cutting," from trancher, trencher "to cut," Old French trenchier (see trench). Economic sense is from 1930.
trannie (n.): also tranny "transsexual person," 1983, from transsexual + -ie. In 1960s and '70s the word was used as a slang shortening of transistor radio and in car magazines for transmission.
tranquil (adj.): mid-15c., a back-formation from tranquility or else from Latin tranquillus "quiet, calm, still." Related: Tranquilly.
tranquility (n.): also tranquillity, late 14c., from Old French tranquilite "peace, happiness" (12c.), from Latin tranquillitatem (nominative tranquillitas) "quietness, stillness; serenity," from tranquillus "quiet, calm, still," perhaps from trans- "over" (here in its intensive sense of "exceedingly") + a root possibly related to quies "rest" (see quiet (n.)).
tranquilize (v.): 1620s, from tranquil + -ize. Related: Tranquilized; tranquilizing; tranquilization.
tranquilizer (n.): 1800, "that which tranquilizes;" from 1824 as "a sedative" (first reference is to ground ivy), agent noun from tranquilize; in reference to one of a large group of anti-anxiety drugs, it is recorded by 1956.
trans-: word-forming element meaning "across, beyond, through, on the other side of, to go beyond," from Latin trans-, from trans (prep.) "across, over, beyond," perhaps originally present participle of a verb *trare-, meaning "to cross," from PIE *tra-, variant of root *tere- (2) "to cross over" (see through). In chemical use indicating "a compound in which two characteristic groups are situated on opposite sides of an axis of a molecule" [Flood].
trans-Atlantic (adj.): also transatlantic, 1779, from trans- "through, across" + Atlantic.
trans-oceanic (adj.): 1827, "situated across the ocean," from trans- + oceanic. Meaning "passing over the sea" is recorded from 1868.
trans.: abbreviation of transitive (adj.).
transact (v.): 1580s, back-formation from transaction, or else from Latin transactus, past participle of transigere "to drive through, accomplish, bring to an end, settle." Related: Transacted; transacting.
transaction (n.): mid-15c., "the adjustment of a dispute, a negotiated agreement, management or settlement of an affair," from Old French transaccion "exchange, transaction," from Late Latin transactionem (nominative transactio) "an agreement, accomplishment," noun of action from past participle stem of transigere "stab through; accomplish, perform, drive or carry through, come to a settlement," from trans- "through" (see trans-) + agere "to drive" (see act (n.)). Meaning "a piece of business" is attested from 1640s. Related: Transactions; transactional.
transaxle (n.): 1958, from transmission axle.
transceiver (n.): 1934, from a merger of transmitter + receiver.
transcend (v.): mid-14c., "escape inclusion in; lie beyond the scope of," from Old French transcendre "transcend, surpass," and directly from Latin transcendere "climb over or beyond, surmount, overstep," from trans- "beyond" (see trans-) + scandere "to climb" (see scan (v.)). Meanings "be surpassing, outdo, excel; surmount, move beyond" are from early 15c. Related: Transcended; transcending.
transcendence (n.): c. 1600, from transcendent + -ence, or else from Medieval Latin transcendentia, from Latin transcendentem. Related: Transcendency.
transcendent (adj.): mid-15c., from Latin transcendentem (nominative transcendens) "surmounting, rising above," present participle of transcendere (see transcend). Related: Transcendently.
transcendental (adj.): 1660s, from Medieval Latin transcendentalis, from Latin transcendentem (see transcendent). Related: Transcendentally. Transcendental meditation attested by 1966.
transcendentalism (n.): 1803, in reference to Kant, later to Schelling; 1842 in reference to the New England religio-philosophical movement among American followers of Schelling; from transcendental + -ism.
transcendentalist (n.): 1803, from transcendental + -ist.
transcontinental (adj.): also trans-continental, 1853 (in transcontinental railroad), American English, from trans- + continental.
transcribe (v.): 1550s, from Latin transcribere "to copy, write again in another place, write over, transfer," from trans- "over" (see trans-) + scribere "write" (see script (n.)). To do it poorly is to transcribble (1746). Related: Transcribed; transcriber; transcribing.
transcript (n.): "written copy of a document," c. 1300, from Medieval Latin transcriptum, neuter past participle of Latin transcribere (see transcribe).
transcriptase (n.): 1963, from transcription + -ase.
transcription (n.): 1590s, from Middle French transcription, from Late Latin transcriptionem (nominative transcriptio), noun of action from past participle stem of transcribere (see transcribe). Biological sense is from 1961. Related: Transcriptional; transcriptionist.
transduce (v.): 1949, back-formation from transducer. Related: Transduced; transducing.