Online Etymology Dictionary

TNT: 1915, abbreviation of trinitrotoluene (1908), from trinitro- indicating three nitro- groups in place of three hydrogen atoms in a compound, + toluene.
to (prep.): Old English to "in the direction of, for the purpose of, furthermore," from West Germanic *to (source also of Old Saxon and Old Frisian to, Dutch too, Old High German zuo, German zu "to"), from PIE pronominal base *do- "to, toward, upward" (source also of Latin donec "as long as," Old Church Slavonic do "as far as, to," Greek suffix -de "to, toward," Old Irish do, Lithuanian da-), from demonstrative *de-.

Not found in Scandinavian, where the equivalent of till (prep.) is used. In Old English, the preposition (go to town) leveled with the adverb (the door slammed to) except where the adverb retained its stress (tired and hungry too); there it came to be written with -oo (see too).

The nearly universal use of to with infinitives (to sleep, to dream, etc.) arose in Middle English out of the Old English dative use of to, and it helped drive out the Old English inflectional endings (though in this use to itself is a mere sign, without meaning).

Commonly used as a prefix in Middle English (to-hear "listen to," etc.), but few of these survive (to-do, together, and time references such as today, tonight, tomorrow -- Chaucer also has to-yeere). To and fro "side to side" is attested from mid-14c. Phrase what's it to you "how does that concern you?" (1819) is a modern form of an old question:
Huæd is ðec ðæs?
[John xxi:22, in Lindisfarne Gospel, c.950]
to-: particle expressing separation, putting asunder, from West Germanic *ti- (source also of Old Frisian ti-, Old High German zi-, German zer-), from Proto-Germanic *tiz-, cognate with Latin-derived dis-. According to OED, some 125 compound verbs with this element are recorded in Old English; their number declined rapidly in Middle English and disappeared by c. 1500 except as conscious archaisms (such as to-shiver "break to pieces;" all to-brast).
to-do (n.): 1570s, from the verb phrase to do, from Old English to don "proper or necessary to be done" (see to + do). Meaning "disturbance, fuss" is first recorded 1827. Similar formation in French affaire, from à "to" + faire "do."
toad (n.): c. 1300, from late Old English tadige, tadie, of unknown origin and according to OED with no known cognates outside English. Applied to loathsome persons from 1560s. Toad-strangler "heavy rain" is from 1919, U.S. Southern dialectal.
toadstone (n.): "stone or stone-like object, supposedly magical (with healing or protective power) and found in the heads of certain toads," 1550s, from toad + stone (n.). Translating Greek batrakhites, Medieval Latin bufonites; compare also French crapaudine (13c.), German krötenstein.
The Crapadine or Toadstone, we speak of before, you shall prove to be a true one, if the Toad lift himself so up against it, when it is shew'd or held to him, as if he would come at it, and leap to catch it away: he doth so much envy that Man should have that stone. ["Eighteen Books of the Secrets of Art & Nature," 1661]
toadstool (n.): late 14c., apparently just what it looks like: a fanciful name from Middle English tadde "toad" (see toad) + stole "stool" (see stool). Toads themselves were regarded as highly poisonous, and this word is "popularly restricted to poisonous or inedible fungi, as distinct from edible "mushrooms" [OED]. Compare toad-cheese, a poisonous fungi; toad's meat (1886), a "rustic" term for toadstool.
toady (n.): "servile parasite," 1826, apparently shortened from toad-eater "fawning flatterer" (1742), originally (1620s) "the assistant of a charlatan," who ate a toad (believed to be poisonous) to enable his master to display his skill in expelling the poison. The verb is recorded from 1827. Related: Toadied; toadying.
toast (v.1): "to brown with heat," late 14c., from Old French toster "to toast, to grill, roast, burn" (12c.), from Vulgar Latin *tostare (source of Italian tostare, Spanish tostar), frequentative of Latin torrere (past participle tostus) "to parch" (see terrain). Related: Toasted; toasting.
toast (n.1): "a call to drink to someone's health," 1700 (but said by Steele, 1709, to date to the reign of Charles II), originally referring to the beautiful or popular woman whose health is proposed and drunk. The custom apparently has its origin in the use of spiced toast (n.2) to flavor drink, the lady being regarded as figuratively adding piquancy to the wine in which her health was drunk. Steele's story ["Tatler," No. 24] is that an (unnamed) beauty of the day was taking the cold waters at Bath, when a gentleman dipped his cup in the water and drank it to her health; another in his company wittily (or drunkenly) replied that, while he did not care for the drink, he would gladly enjoy the toast. Meaning "one whose health is proposed and drunk to" is from 1746. Toast-master attested from 1749.
toast (n.2): "piece of bread browned by fire or dry heat," early 15c., from toast (v.1); originally as something added to wine, ale, etc. From 17c. in the modern sense as something eaten on its own with a spread. Slang meaning "a goner, person or thing already doomed or destroyed" is recorded by 1987, perhaps from notion of computer circuits being "fried," and with unconscious echoes of earlier figurative phrase to be had on toast (1886) "to be served up for eating."
toast (v.2): "to propose or drink a toast," 1700, from toast (n.1). This probably is the source of the Jamaican and African-American vernacular word meaning "extemporaneous narrative poem or rap" (1962). Related: Toasted; toasting.
toaster (n.): 1580s, agent noun from toast (v.1). Electrical type is from 1913. In reference to a person who proposes or pledges a drinking toast, from 1704 (from toast (v.2)). Toaster-oven attested from 1957.
toasty (adj.): "warm and comfortable," 1882, from toast (n.2) + -y (2). Related: Toastiness.
tobacco (n.): 1580s, from Spanish tabaco, in part from an Arawakan language of the Caribbean (probably Taino), said to mean "a roll of tobacco leaves" (according to Las Casas, 1552) or "a kind of pipe for smoking tobacco" (according to Oviedo, 1535). Scholars of Caribbean languages lean toward Las Casas' explanation. But Spanish tabaco (also Italian tabacco) was a name of medicinal herbs from early 15c., from Arabic tabbaq, attested since 9c. as the name of various herbs. So the word may be in part a European one transferred to an American plant. The West Indian island of Tobago was said to have been named by Columbus in 1498 from Haitian tambaku "pipe," in reference to the native custom of smoking dried tobacco leaves [Room].

Cultivation in France began 1556 with an importation of seed by Andre Thevet; introduced in Spain 1558 by Francisco Fernandes. Tobacco Road as a mythical place representative of rural Southern U.S. poverty is from the title of Erskine Caldwell's 1932 novel. Early German and Portuguese accounts of Brazil also record another name for tobacco, bittin or betum, evidently a native word in South America, which made its way into 17c. Spanish, French, and English as petun, petumin, etc., and which is preserved in petunia and butun, the Breton word for "tobacco."
Many haue giuen it [tobacco] the name, Petum, whiche is in deede the proper name of the Hearbe, as they whiche haue traueiled that countrey can tell. [John Frampton, translation of Nicolás Monardes' "Joyful Newes Oute of the Newe Founde Worlde," 1577]
tobacconist (n.): "dealer in tobacco," 1650s, from tobacco + -ist + abnormal inserted consonant; earlier meaning was "person addicted to tobacco" (1590s).
Tobias: masc. proper name, from Late Latin Tobias, from Greek Tobias, from Hebrew Tobhiyyah, literally "the Lord is my Good," from Hebrew tobh "good." Toby is a short form.
toboggan (n.): "long, flat-bottomed sled," 1829, from Canadian French tabagane, from an Algonquian language, such as Maleseet /thapaken/. The verb is recorded from 1846. As American English colloquial for a type of long woolen cap, it is recorded from 1929 (earlier toboggan cap, 1928), presumably because one wore such a cap while tobogganing.
Toby: familiar form of masc. proper name Tobias, in various colloquial usages, such as "jug" (1840), "drinking mug in the form of a stout old man;" as a type of collar (1882) it refers to that worn by the dog Toby in 19c. Punch and Judy shows. Also in Toby show (by 1942, American English) "comedy act based on the stock character of a boisterous, blundering yokel."
toc: word used for the letter T in radio communication, 1898.
toccata (n.): 1724, from Italian toccata, from toccare "to touch," from Vulgar Latin *toccare (see touch (v.)). "A composition for a keyboard instrument, intended to exhibit the touch and technique of the performer, and having the air of an improvisation" [OED].
Tocharian: in reference to an extinct people and Indo-European language of Chinese Turkestan, 1927, from French tocharien, from Greek Tokharoi (Strabo), name of an Asiatic people who lived in the Oxus valley in ancient times. Earlier Tocharish (1910), from German tocharisch. The identification of this culture with the people named by Strabo was suggested in 1907 by F.W.K. Müller and "is obviously erroneous" (Klein).
tocsin (n.): "alarm bell," 1580s, from Middle French toquassen "an alarm bell, the ringing of an alarm bell" (late 14c.), from Old Provençal tocasenh, from tocar "to strike" (from Vulgar Latin *toccare "strike a bell;" see touch (v.)) + senh "bell, bell note," from Late Latin signum "bell, ringing of a bell," in Latin "mark, signal" (see sign (n.)). The current English spelling is from 1794, adopted from modern French.
today (adv.): Old English todæge, to dæge "on (this) day," from to "at, on" (see to) + dæge, dative of dæg "day" (see day). Meaning "in modern times" is from c. 1300. As a noun from 1530s. Generally written as two words until 16c., after which it usually was written to-day until early 20c.

Similar constructions exist in other Germanic languages, such as Dutch van daag "from-day," Danish and Swedish i dag "in day." German heute is from Old High German hiutu, from Proto-Germanic *hiu tagu "on (this) day," with first element from PIE pronominal stem *ki-, represented by Latin cis "on this side."
Todd: masc. proper name, also a surname (late 12c.), from Middle English todde "fox," a Northern English word of unknown origin.
toddle (v.): "to run or walk with short, unsteady steps," c. 1600, Scottish and northern British, of uncertain origin, possibly related to totter (1530s); an earlier sense of "to toy, play" is found c. 1500. Related: Toddled; toddling.
toddler (n.): 1793, agent noun from toddle. Toddlekins is from 1839.
toddy (n.): 1610s, alteration of taddy (1610s), tarrie (c. 1600) "beverage made from fermented palm sap," from Hindi tari "palm sap" (in which the -r- sounds close to an English -d-), from tar "palm tree," from Sanskrit tala-s, probably from a Dravidian language (compare Kannada tar, Telugu tadu). Meaning "beverage made of alcoholic liquor with hot water, sugar, and spices" first recorded 1786.
toe (n.): Old English ta "toe" (plural tan), contraction of *tahe (Mercian tahæ), from Proto-Germanic *taihwo (source also of Old Norse ta, Old Frisian tane, Middle Dutch te, Dutch teen (perhaps originally a plural), Old High German zecha, German Zehe "toe"). Perhaps originally meaning "fingers" as well (many PIE languages still use one word to mean both fingers and toes), and thus from PIE root *deik- "to show" (see diction).
Þo stode hii I-armed fram heued to þe ton. [Robert of Gloucester, "Chronicle," c. 1300]
The old plural survived regionally into Middle English as tan, ton. To be on (one's) toes "alert, eager" is recorded from 1921. To step on (someone's) toes in the figurative sense "give offense" is from late 14c. Toe-hold "support for the toe of a boot in climbing" is from 1880.
toe (v.): "touch or reach with the toes," 1813, from toe (n.). First recorded in expression toe the mark, which seems to be nautical in origin.
The chief mate ... marked a line on the deck, brought the two boys up to it, making them "toe the mark." [R.H. Dana, "Two Years Before the Mast," 1840]
Related: Toed; toeing.
toenail (n.): also toe-nail, 1690s, from toe (n.) + nail (n.).
toff (n.): lower-class London slang for "stylish dresser, man of the smart set," 1851, said by OED to be probably an alteration of tuft, formerly an Oxford University term for a nobleman or gentleman-commoner (1755), in reference to the gold ornamental tassel worn on the caps of undergraduates at Oxford and Cambridge whose fathers were peers with votes in the House of Lords.
toffee (n.): 1825, tuffy, toughy, southern British dialectal variant of taffy. Modern spelling recorded by 1843.
toft (n.): "homestead, site of a house," late Old English, from Old Norse topt "homestead," from Proto-Germanic *tumfto, from PIE *dem- "house, household" (see domestic).
tofu (n.): soy bean curd, 1876, from Japanese tofu, from Chinese doufu, from dou "beans" + fu "rotten."
tog (n.): 1708, "outer garment," shortened from togman "cloak, loose coat" (1560s), thieves' cant word, formed from French togue "cloak," from Latin toga (see toga). Middle English toge "toga" (14c.) also was a cant word for "a coat."
toga (n.): c. 1600, from Latin toga "cloak or mantle," from PIE *tog-a- "covering," from root *(s)teg- "to cover" (see stegosaurus). The outer garment of a Roman citizen in time of peace.
The toga as the Roman national dress was allowed to be worn by free citizens only. A stranger not in full possession of the rights of a Roman citizen could not venture to appear in it. Even banished Romans were in imperial times precluded from wearing it. The appearance in public in a foreign dress was considered as contempt of the majesty of the Roman people. Even boys appeared in the toga, called, owing to the purple edge attached to it (a custom adopted from the Etruscans) toga praetexta. On completing his sixteenth, afterward his fifteenth, year (tirocinium fori), the boy exchanged the toga praetexta for the toga virilis, pura, or libera--a white cloak without the purple edge. Roman ladies (for these also wore the toga) abandoned the purple edge on being married. [Guhl & Koner, "The Life of the Greeks and Romans," transl. Francis Hueffer, 1876]
Breeches, like the word for them (Latin bracae) were alien to the Romans, being the dress of Persians, Germans, and Gauls, so that bracatus "wearing breeches" was a term in Roman geography meaning "north of the Alps." College fraternity toga party was re-popularized by movie "Animal House" (1978), but this is set in 1962 and the custom seems to date from at least the mid-1950s.
Down on Prospect Street, Campus Club held a toga party, at which everyone wore togas. Charter held a come-as-you-are party, at which everyone wore what they happened to have on, and Cloister held a party called "A Night in Tahiti," at which we'd hate to guess what everyone wore. The borough police reported that only one false alarm was turned in. ["Princeton Alumni Weekly," March 19, 1954]
together (adv.): Old English togædere "so as to be present in one place, in a group, in an accumulated mass," from to (see to) + gædere "together" (adv.), apparently a variant of the adverb geador "together," from Proto-Germanic *gaduri- "in a body," from PIE *ghedh- "to unite, join, fit" (see good, and compare gather).

In reference to single things, "so as to be unified or integrated," from c. 1300. Adjective meaning "self-assured, free of emotional difficulties" is first recorded 1966. German cognate zusammen has as second element the Old High German verbal cognate of English same (Old English also had tosamne "together").
togetherness (n.): 1650s, "state of being together," from together + -ness. Sense of "fellowship, fellow-feeling," is from 1930.
toggery (n.): "clothes collectively," 1812, from tog + -ery.
toggle (n.): 1769, "pin passed through the eye of a rope, strap, or bolt to hold it in place," a nautical word of uncertain origin, perhaps a frequentative form of tog "tug." As a kind of wall fastener it is recorded from 1934. Toggle bolt is from 1794; toggle switch, the up-and-down sort, first attested 1938. In computing by 1979, in reference to a key which alternates the function between on and off when struck.
toggle (v.): 1836, "make secure with a toggle," from toggle (n.). Meaning "alternate back and forth between opposite actions" is by 1982. Related: Toggled; toggling.
togs (n.): "clothes," 1779, plural of tog (q.v.).
toil (n.1): "hard work," c. 1300, originally "turmoil, contention, dispute," from Anglo-French toil (13c.), from toiler "agitate, stir up, entangle, writhe about," from Old French toeillier "drag about, make dirty" (12c.), usually said to be from Latin tudiculare "crush with a small hammer," from tudicula "mill for crushing olives, instrument for crushing," from Latin tudes "hammer," from PIE *tud-, variant of *(s)teu- "to push, stroke, knock, beat" (see obtuse). Sense of "hard work, labor" (1590s) is from the related verb (see toil (v.)).
toil (n.2): "net, snare," 1520s, from Middle French toile "hunting net, cloth, web" (compare toile d'araignée "cobweb"), from Old French toile "cloth" (11c.), from Latin tela "web, net, warp of a fabric," from PIE *teks- "to weave" (see texture (n.)). Now used largely in plural (as in caught in the toils of the law).
toil (v.): early 14c., toilen, "pull at, tug," from Anglo-French toiller, Old French toellier "pull or drag about" (see toil (n.1)). Intransitive meaning "struggle, work hard, labor for considerable time" is from late 14c., perhaps by influence of till (v.). Related: Toiled; toiling.
toile (n.): type of heavy, coarse cloth, c. 1400, from Old French toile "linen cloth, canvas" (see toil (n.2)). As a type of dress material, from 1794.
toilet (n.): 1530s, earliest in English in an obsolete sense "cover or bag for clothes," from Middle French toilette "a cloth; a bag for clothes," diminutive of toile "cloth, net" (see toil (n.2)). Toilet acquired an association with upper class dressing by 18c., through the specific sense "a fine cloth cover on the dressing table for the articles spread upon it;" thence "the articles, collectively, used in dressing" (mirror, bottles, brushes, combs, etc.). Subsequent sense evolution in English (mostly following French uses) is to "act or process of dressing," especially the dressing and powdering of the hair (1680s); then "a dressing room" (1819), especially one with a lavatory attached; then "lavatory or porcelain plumbing fixture" (1895), an American euphemistic use.

Toilet paper is attested from 1884 (the Middle English equivalent was arse-wisp). Toilet training is recorded from 1940.
toiletries (n.): "odds and ends used in grooming," 1924, from toiletry (1892); see toilet + -ry.
toilsome (adj.): 1580s, from toil (v.) + -some (1). An earlier word was toilous (early 15c.). The opposite, toilless (c. 1600) is much less common.