Online Etymology Dictionary

tip (v.4): "put a tip on, adorn with a tip," late 14c., from tip (n.) or Old Norse typpa. Related: Tipped; tipping.
tip-off (n.): 1901 in reference to information, from tip (v.2) + off (adv.). From 1924 in basketball, from tip (v.3).
tip-top (n.): "extreme top," 1702, from tip (n.1) + top (n.1). Hence, "most excellent."
Tipperary: place in Ireland, from Irish Tiobraid Arann "well of the Ara (river)."
tippet (n.): c. 1300, of unknown origin; perhaps from Old English tæppet "carpet, hanging."
tipple (v.): c. 1500 (implied in tippling), "sell alcoholic liquor by retail," of unknown origin, possibly from a Scandinavian source (such as Norwegian dialectal tipla "to drink slowly or in small quantities"). Meaning "drink (alcoholic beverage) too much" is first attested 1550s. Related: Tippled.
tippler (n.): late 14c., "seller of alcoholic liquors," of uncertain origin (see tipple). In the sense of "habitual drinker" it dates from 1570s.
tipstaff (n.): 1540s, "tipped staff" (truncheon with a tip or cap of metal) carried as an emblem of office, from tip (n.) + staff (n.). As the name of an official who carries one (especially a sheriff's officer, bailiff, constable, court crier, etc.) it is recorded from 1560s.
tipster (n.): "one who provides private information," 1862, from tip (v.2) + -ster.
tipsy (adj.): 1570s, from tip (v.1); compare drowsy, flimsy, tricksy. Later associated with tipple. Tipsy-cake (1806) was stale cake saturated with wine or liquor.
tiptoe (n.): late 14c., from tip (n.1) + toe (n.). As an adverb from 1590s; as a verb from 1630s. Related: Tiptoes (late 14c.), also tiptoon; tip-toed. Tippy-toes is from 1820.
tirade (n.): "a long, vehement speech, a 'volley of words,' " 1801, from French tirade "a volley, a shot; a pull; a long speech or passage; a drawing out" (16c.), from tirer "draw out, endure, suffer," or the French noun is perhaps from or influenced by cognate Italian tirata "a volley," from past participle of tirare "to draw." The whole Romanic word group is of uncertain origin. Barnhart suggests it is a shortening of the source of Old French martirer "endure martyrdom" (see martyr).
tire (v.1): "to weary," also "to become weary," Old English teorian (Kentish tiorian) "to fail, cease; become weary; make weary, exhaust," of uncertain origin; according to Watkins possibly from a PIE *deu-s-, suffixed form of root *deu- (1) "to lack, be wanting." Related: Tired; tiring.
tire (n.): late 15c., "iron plates forming a rim of a carriage wheel," probably from tire "equipment, dress, covering" (c. 1300), a shortened form of attire (n.). The notion is of the tire as the dressing of the wheel. The original spelling was tyre, which had shifted to tire in 17c.-18c., but since early 19c. tyre has been revived in Great Britain and become standard there. Rubber ones, for bicycles (later automobiles) are from 1877. A tire-iron originally was one of the iron plates; as a device for separating a tire from a wheel, by 1909.
tire (v.2): "furnish with a tire," 1899, from tire (n.).
tired (adj.): "exhausted, fatigued, weary," early 15c., past participle adjective from tire (v.).
tiredness (n.): 1550s, from tired + -ness.
tireless (adj.): 1590s, "indefatigable," from tire (v.) + -less. From 1862 in the sense "without a tire," from tire (n.). Related: Tirelessly.
tiresome (adj.): "tedious," c. 1500, from tire (v.) + -some (1). Related: Tiresomely; tiresomeness.
Tironian: of or pertaining to Marcus Tullius Tiro, Cicero's scribe and namesake, 1828, especially in reference to the Tironian Notes (Latin notæ Tironianæ), a system of shorthand said to have been invented by him (see ampersand).
Although involving long training and considerable strain on the memory, this system seems to have practically answered all the purposes of modern stenography. It was still in familiar use as late as the ninth century. [Century Dictionary]
tisane (n.): medicinal tea, 1931, from French tisane; earlier ptisan (14c.), from Latin ptisana, from Greek ptisane "crushed barley," related to ptissein "to winnow, crush, peel" (see pestle).
tissue (n.): mid-14c., "band or belt of rich material," from Old French tissu "a ribbon, headband, belt of woven material" (c. 1200), noun use of tissu "woven, interlaced," past participle of tistre "to weave," from Latin texere "to weave, to make" (see texture (n.)). The biological sense is first recorded 1831, from French, introduced c. 1800 by French anatomist Marie-François-Xavier Bichal (1771-1802). Meaning "piece of absorbent paper used as a handkerchief" is from 1929. Tissue-paper is from 1777, supposedly so called because it was made to be placed between tissues to protect them.
tit (n.1): "breast," Old English titt "teat, nipple, breast" (a variant of teat). But the modern slang tits (plural), attested from 1928, seems to be a recent reinvention, used without awareness of the original form, from teat or from dialectal and nursery diminutive variant titties (pl.).
tit (n.2): 1540s, a word used for any small animal or object (as in compound forms such as titmouse, tomtit, etc.); also used of small horses. Similar words in related senses are found in Scandinavian (Icelandic tittr, Norwegian tita "a little bird"), but the connection and origin are obscure; perhaps, as OED suggests, the word is merely suggestive of something small. Used figuratively of persons after 1734, but earlier for "a girl or young woman" (1590s), often in deprecatory sense of "a hussy, minx."
tit for tat: 1550s, possibly an alteration of tip for tap "blow for blow," from tip (v.3) "tap" + tap "touch lightly." Perhaps influenced by tit (n.2).
titan (n.): early 15c., from Latin titan, from Greek titan, member of a mythological race of giants who attempted to scale heaven by piling Mount Pelion on Mount Ossa but were overthrown by Zeus and the other gods. They descended from Titan, elder brother (or grandson) of Kronos. The name is perhaps from tito "sun, day," which probably is a loan-word from a language of Asia Minor. Sense of "person or thing of enormous size or ability" first recorded 1828. Applied to planet Saturn's largest satellite in 1831; it was discovered 1655 by Dutch astronomer Christiaan Huygens, who named it Saturni Luna "moon of Saturn." Related: Titaness; titanian.
titanic (adj.): "gigantic, colossal," 1709, from titan + -ic. The British passenger liner R.M.S. Titanic sank April 15, 1912, and the name became symbolic of the destruction of supposedly indestructible.
titanium (n.): metallic element, 1796, Modern Latin, named in 1795 by German chemist and mineralogist Martin Heinrich Klaproth (1743-1817) from Latin Titan (see titan) as "sons of the earth." He previously had named uranium. A pure specimen was not isolated until 1887.
tithe (n.): a tenth part (originally of produce) due as support of the clergy, c. 1200, from Old English teogoþa (Anglian), teoþa (West Saxon) "tenth," from Proto-Germanic *teguntha, from PIE *dekmto-, from *dekm "ten" (see ten). Retained in ecclesiastical sense while the form was replaced in ordinal use by tenth.
tithe (v.): Old English teoþian "to pay one-tenth," from the root of tithe (n.). As "to impose a payment of a tenth," late 14c. Related: Tithed; tithing.
tither (n.): late 14c., "one who pays a tithe," agent noun from tithe (v.). As "one who exacts a tithe," 1590s.
titi (n.): type of small South American monkey, 1832, from native name in Tupi, probably imitative.
Titian (n.): 1824, "a painting by Venetian painter Tiziano Vecellio" (c. 1490-1576), from Englished form of his name. Often also in reference to the tint of bright auburn hair favored by him in his work.
titillate (v.): 1610s, back-formation from titillation. Related: Titillated; titillating.
titillation (n.): early 15c., "pleasing excitement," from Latin titillationem (nominative titillatio) "a tickling," noun of action from past participle stem of titillare "to tickle," imitative of giggling.
titivate (v.): 1805, perhaps from tidy, "with a quasi-Latin ending" [OED] as in cultivate.
title (n.): c. 1300, "inscription, heading," from Old French title "title or chapter of a book; position; legal permit" (12c., Modern French titre, by dissimilation), and in part from Old English titul, both from Latin titulus "inscription, label, ticket, placard, heading; honorable appellation, title of honor," of unknown origin. Meaning "name of a book, play, etc." first recorded mid-14c. The sense of "name showing a person's rank" in English is first attested 1580s. Sports championship sense attested from 1913 (originally in lawn tennis), hence titlist (1913).
title (v.): "to furnish with a title," early 14c., from title (n.). Related: Titled; titling.
titmouse (n.): small, active bird, early 14c., titmose, from tit (n.2), expressing something small, + Old English mase "titmouse," from Proto-Germanic *maison (source also of Dutch mees, German meise), from adj. *maisa- "little, tiny." Spelling influenced 16c. by unrelated mouse, "when mose had long been obsolete as an independent word" [OED]. The proper plural is titmouses.
titrate (v.): 1854, with -ate (2) + French titrer, from titre "standard, title," also "fineness of alloyed gold" (see title (n.)).
titration (n.): in chemistry, "the establishment of a standard strength or degree of concentration of a solution," 1864, noun of action from titrate (v.).
titter (v.): 1610s, "giggle in a suppressed or nervous way," probably of imitative origin. Related: Tittered; tittering. The noun is first recorded 1728.
titties (n.): 1746, tetties (plural), a nursery or dialect diminutive variant of teats (see teat).
Margery. Come, be quite;--be quite, es zey, a grabbling o' wone's Tetties.---Es wont ha' ma Tetties a grabbled zo ; ner es wont be mullad and foulad.---Stand azide; come, gi' o'er. ["Exmoor Courtship, or, A Suitoring Discourse, in the Devonshire Dialect and Mode, near the forest of Exmoor," 1746]
tittle (n.): late 14c., "small stroke or point in writing" (Wyclif, in Matt. v:18), translating Latin apex in Late Latin sense of "accent mark over a vowel," which itself translates Greek keraia (literally "a little horn"), used by the Greek grammarians of the accents and diacritical points, in this case a Biblical translation of Hebrew qots, literally "thorn, prick," used of the little lines and projections by which the Hebrew letters of similar form differ from one another.

Wyclif's word is borrowed from a specialized sense of Latin titulus (see title (n.)), which was used in Medieval Latin (and in Middle English and Old French) to indicate "a stroke over an abridged word to indicate letters missing" (and compare Provençal titule "the dot over -i-").
As apex was used by the Latin grammarians for the accent or mark over a long vowel, titulus and apex became to some extent synonymous; hence Wyclif's use of titil, titel to render L. apex [OED]
Compare tilde, which is the Spanish form of the same word.
titular (adj.): 1590s, from or based on Middle French titulaire (16c.), from Latin titulus (see title) + -ar. Related: Titulary.
tix (n.): short for tickets, by 1944 in "Billboard" headlines.
tizzy (n.): 1922, American English colloquial, of uncertain origin, perhaps related to slang tizzy "sixpence piece" (1804), a corruption of tester, a name for the coin (see tester (n.2)).
TLC (n.): by 1953 as an abbreviation of tender loving care.
Tlingit (n.): Indian group in southwestern Alaska and adjacent parts of Canada, 1865, the people's word for themselves, literally "human beings."
tmesis (n.): 1580s, from Greek tmesis "a cutting," related to temnein "to cut," tome "a cutting" (see tome). The separation of the elements of a compound word by the interposition of another word or words (such as a whole nother).