Online Etymology Dictionary

T: to cross one's t's (and dot one's i's) "to be exact" is attested from 1849. Phrase to a T "exactly" is recorded from 1690s, though the exact signification remains uncertain despite much speculation. The measuring tool called a T-square (sometimes suggested as the source of this) is recorded by that name only from 1785. The T-cell (1970) so called because they are derived from the thymus. As a medieval numeral, T represented 160.
T and A (n.): 1972, short for tits and ass (a phrase attributed to Lenny Bruce), in reference to salacious U.S. mass media; earlier it was medical shorthand for "tonsils and adenoids" (1942).
T-bone (n.): type of steak, 1916, so called from the T-shaped bone that runs through it. The verb meaning "to strike (another car, bus, etc.) from the side" is by 1970, from adjectival use in reference to crashes, attested from 1952, from the position of the two vehicles at impact.
T-shirt (n.): 1920, in reference to the shape it makes when laid out flat (t-shirt is thus incorrect).
ta: 1772, "natural infantile sound of gratitude" [Weekley].
ta'en: contraction of taken.
ta-ta: also tata, "good-bye," familiar salutation in parting, 1823, a word first recorded as infant's speech. Abbreviation T.T.F.N., "ta-ta for now," popularized 1941 by BBC radio program "ITMA," where it was the characteristic parting of the cockney cleaning woman character Mrs. Mopp, voiced by Dorothy Summers.
tab (n.1): "small flap or strip of material," c. 1600, possibly from a dialectal word, of uncertain origin. Often interchangeable with tag (n.1). Compare also Middle English tab "strap or string" (mid-15c.), Norwegian dialectal tave "piece of cloth, rag."
tab (n.2): "account, bill, check," 1888, American English colloquial, probably a shortened form of tabulation or of tablet in the sense "a sheet for writing on." Figurative phrase keep a tab on is recorded from 1890.
tab (n.3): 1961, shortened form of tablet (especially one of sugar containing LSD). As an abbreviation of tabloid (newspaper) it is 1990s slang. As a short form of tabulator key of a typewriter (later computer) it is recorded from 1916.
tab (v.): "designate, label, name," 1924, earlier "affix a tab to" 1872 (implied in tabbed), perhaps an alteration of tag (v.2). Related: Tabbing. Also see tab (n.1).
tabacco (n.): obsolete form of tobacco.
tabagie (n.): 1819, from French tabagie (17c.), from tabac "tobacco" (see tobacco) + -age. A group of smokers who meet in club fashion; a "tobacco-parliament." In German, a Rauchkneipe.
tabard (n.): c. 1300 (late 13c. as a surname), from Old French tabart "simple sleeveless overtunic," also "heavy overmantel" (12c.), of unknown origin; Diez suggests Latin tapete "figured cloth." Compare Medieval Latin tabardum, early Spanish tabardo, Italian tabarro. Originally a coarse, sleeveless upper garment worn by peasants and others who worked out-of-doors; later a knight's surcoat (hence the name of the tavern in "Canterbury Tales").
Tabasco: proprietary name of a type of hot sauce, 1876, (the sauce so called from 1650s, originally Tavasco), named for the state in Mexico, perhaps because the pepper sauce was first encountered there by U.S. and European travelers. The trademark (by Edward Avery McIlhenny) claims use from c. 1870. The place name is from an unidentified Mexican Indian language and of unknown etymology.
tabbouli (n.): also tabouli, tabbouleh, Middle Eastern vegetable salad, 1955, from Arabic tabbula.
tabby (n.): 1630s, "striped silk taffeta," from French tabis "a rich, watered silk" (originally striped), from Middle French atabis (14c.), from Arabic 'attabi, from 'Attabiyah, a neighborhood of Baghdad where such cloth was made, said to be named for prince 'Attab of the Omayyad dynasty. As an adjective from 1630s.

Tabby cat, one with a striped coat, is attested from 1690s; shortened form tabby first attested 1774. "The wild original of the domestic cat is always of such coloration" [Century Dictionary]. Sense of "female cat" (1826) may be influenced by the fem. proper name Tabby, a pet form of Tabitha, which was used in late 18c. as slang for "spiteful spinster, difficult old woman."
tabernacle (n.): mid-13c., "portable sanctuary carried by the Israelites in the wilderness," from Old French tabernacle "the Jewish Tabernacle; tent, canopy; tomb, monument" (12c.), from Latin tabernaculum "tent," especially "a tent of an augur" (for taking observations), diminutive of taberna "hut, cabin, booth" (see tavern).

Use of the word in English transferred late 14c. to the Temple in Jerusalem (which continued its function). Sense of "house of worship" first recorded 1690s. Also in Biblical language, "the body as the temporary abode of the soul" (late 14c.). The Jewish Feast of Tabernacles (mid-October) was observed as a thanksgiving for harvest. Related: Tabernacular.
tabes (n.): "emaciation," 1650s, medical Latin, from Latin tabes "a melting, wasting away, putrefaction," from tabere "to melt, waste away, be consumed," from PIE *ta- "to melt, dissolve" (see thaw (v.)).
Tabitha: fem. proper name, from Late Latin, from Greek Tabitha, from Aramaic tabhyetha, emphatic of tabhya "gazelle," which is related to Hebrew tzebhi (fem. tzebhiyyah), Arabic zaby.
tabla (n.): pair of drums used in northern Indian music, 1865, from Hindi, from Arabic tabl "a drum played with the hand."
tablature (n.): type of musical notation for lute or stringed instrument, 1570s, from French tablature (1550s), from Italian tavolatura (also Medieval Latin tabulatura), from Late Latin tabulare, from Latin tabula "table, list, schedule" (see table (n.)). "It differed from the more general staff-notation in that it aimed to express not so much the pitch of the notes intended as the mechanical process by which on the particular instrument those tones were to be produced" [Century Dictionary].
table (n.): late 12c., "board, slab, plate," from Old French table "board, square panel, plank; writing table; picture; food, fare" (11c.), and late Old English tabele "writing tablet, gaming table," from Germanic *tabal (source also of Dutch tafel, Danish tavle, Old High German zabel "board, plank," German Tafel). Both the French and Germanic words are from Latin tabula "a board, plank; writing table; list, schedule; picture, painted panel," originally "small flat slab or piece" usually for inscriptions or for games (source also of Spanish tabla, Italian tavola), of uncertain origin, related to Umbrian tafle "on the board."

The sense of "piece of furniture with the flat top and legs" first recorded c. 1300 (the usual Latin word for this was mensa (see mensa); Old English writers used bord (see board (n.1)). Especially the table at which people eat, hence "food placed upon a table" (c. 1400 in English). The meaning "arrangement of numbers or other figures on a tabular surface for convenience" is recorded from late 14c. (as in table of contents, mid-15c.).

Figurative phrase turn the tables (1630s) is from backgammon (in Old and Middle English the game was called tables). Table talk "familiar conversation around a table" is attested from 1560s, translating Latin colloquia mensalis. Table-manners is from 1824. Table-hopping is first recorded 1943. The adjectival phrase under-the-table "hidden from view" is recorded from 1949; to be under the table "passed out from excess drinking" is recorded from 1913. Table tennis "ping-pong" is recorded from 1887. Table-rapping in spiritualism, supposedly an effect of supernatural powers, is from 1853.
table (v.): mid-15c., "enter into a list, form into a list or catalogue," also "provide with food," from table (n.). In parliamentary sense, 1718, originally "to lay on the (speaker's) table for discussion;" but in U.S. political jargon it has chiefly the sense of "to postpone indefinitely" (1866) via notion of "lay aside for future consideration." Related: Tabled; tabling.
table-d'hote (n.): "common table for guests at a hotel," French, table-d'hôte, literally "table of the host;" see table (n.) + host (n.).
table-land (n.): 1690s, from table (n.) + land (n.).
tableau (n.): 1690s, "a picturesque or graphic description or picture," from French tableau "picture, painting" (12c.), from Old French table "slab, writing tablet" (see table (n.)) + diminutive suffix -eau, from Latin -ellus. Hence tableau-vivant (1817) "person or persons silent and motionless, enacting a well-known scene, incident, painting, etc.," 19c. parlor game, literally "living picture."
tablecloth (n.): also table-cloth, "cloth for covering the top of a table," mid-15c., from table (n.) + cloth.
tablespoon (n.): spoon used in table-service, 1763, from table (n.) + spoon (n.).
tablet (n.): c. 1300, "slab or flat surface for an inscription" (especially the two Mosaic tables of stone), from Old French tablete "small table, merchant's display counter" (13c., Modern French tablette), diminutive of table "slab," or from Medieval Latin tabuleta (source also of Spanish tableta, Italian tavoletta), diminutive of Latin tabula (see table (n.)). The meaning "lozenge, pill" is first recorded 1580s; that of "pad of writing paper" in 1880.
tableware (n.): also table-ware, 1799, from table (n.) + ware (n.).
tabloid (n.): 1884, Tabloid, "small tablet of medicine," trademark name (by Burroughs, Wellcome and Co.) for compressed or concentrated chemicals and drugs, a hybrid formed from tablet + Greek-derived suffix -oid. By 1898, it was being used figuratively to mean a compressed form or dose of anything, hence tabloid journalism (1901), and newspapers that typified it (1917), so called for having short, condensed news articles and/or for being small in size. Associated originally with Alfred C. Harmsworth, editor and proprietor of the "London Daily Mail."
Mr. Harmsworth entered a printing office twenty years ago as office-boy, and today owns thirty periodicals besides The Mail. Upon a friendly challenge from Mr. Pulitzer of The New York World, the English journalist issued the first number of The World for the new century in the ideal form. The size of the page was reduced to four columns and the general make-up was similar in appearance to that of one of the weekly magazines. Current news was presented in condensed and tabulated form, of which the editor says: "The world enters today upon the twentieth or time-saving century. I claim that by my system of condensed or tabloid journalism hundreds of working hours can be saved each year." ["The Twentieth Century Newspaper," in "The Social Gospel," February 1901]
taboo (adj.): also tabu, 1777 (in Cook's "A Voyage to the Pacific Ocean"), "consecrated, inviolable, forbidden, unclean or cursed," explained in some English sources as being from Tongan (Polynesian language of the island of Tonga) ta-bu "sacred," from ta "mark" + bu "especially." But this may be folk etymology, as linguists in the Pacific have reconstructed an irreducable Proto-Polynesian *tapu, from Proto-Oceanic *tabu "sacred, forbidden" (compare Hawaiian kapu "taboo, prohibition, sacred, holy, consecrated;" Tahitian tapu "restriction, sacred, devoted; an oath;" Maori tapu "be under ritual restriction, prohibited"). The noun and verb are English innovations first recorded in Cook's book.
tabor (n.): also tabour, "small drum resembling a tamborine," c. 1300, from Old French tabour, tabur "drum; din, noise, commotion" (11c.), probably from Persian tabir "drum," but evolution of sense and form are uncertain; compare tambourine.
tabula rasa (n.): "the mind in its primary state," 1530s, from Latin tabula rasa, literally "scraped tablet," from which writing has been erased, thus ready to be written on again, from tabula (see table (n.)) + rasa, fem. past participle of radere "to scrape away, erase" (see raze). A loan-translation of Aristotle's pinakis agraphos, literally "unwritten tablet" ("De anima," 7.22).
tabular (adj.): "table-shaped," 1650s, from French tabulaire or directly from Latin tabularis "of a slab or tablet, of boards or planks," from tabula "slab" (see table (n.)). Meaning "arranged in a list or columns; ascertained or computed by means of tables" is from 1710.
tabulate (v.): "to put into form of a table, collect or arrange in columns," 1734, from Latin tabula (see table (n.)) + -ate (2). Earlier in the more literal Latin sense "lay a floor" (1650s). Related: Tabulated; tabulating.
tabulation (n.): "act or process of making tabular arrangements," 1803, noun of action from tabulate (v.). Latin tabulatio meant "a flooring over."
tabulator (n.): 1848, agent noun from tabulate.
tace: "be silent!" Latin imperative of tacere "to be silent" (see tacit).
tacet: musical instruction, 1724, from Latin tacet "is silent," third person singular present indicative of tacere (see tacit).
tacho-: word-forming element meaning "speed," from Latinized form of Greek takho-, comb. form of takhos "speed, swiftness, fleetness, velocity," related to takhys "swift," of unknown origin.
tachometer (n.): speed-measuring instrument, 1810, coined by inventor, Bryan Donkin, from tacho- "speed" + -meter. Related: Tachometry.
tachy-: word-forming element meaning "rapid, swift, fast," from Latinized comb. form of Greek takhys "swift, rapid, hasty," related to takhos "speed, swiftness," of uncertain origin.
tachycardia (n.): "rapid heartbeat," 1868, Modern Latin, coined 1867 by German-born physician Hermann Lebert (1813-1878) from tachy- "swift" + Latinized form of Greek kardia "heart," from PIE root *kerd- (1) "heart" (see heart (n.)).
tachygraphy (n.): "shorthand, stenography," 1640s, from Latinized form of Greek takhygraphia, from takhys "swift" (see tachy-) + -graphia (see -graphy). Related: Tachygraphic; tachygrapher "stenographer" (especially among the ancients; see Tironian).
tachymeter (n.): surveying instrument, 1836, from tachy- "swift" + -meter. Related: Tachymetry.
M. GAETANO CAÏRO has invented an instrument, to which he has given the name of Tachymeter (rapid measurer). Its object is to give the area of plane surfaces bounded by any outline whatever, without the necessity of any arithmetical operation. ["Magazine of Popular Science and Journal of the Useful Arts," Volume 2, 1836]
tachyon (n.): 1967, hypothetical faster-than-light particle, from tachy- "swift" + -on.
tachypnea (n.): "hysterical rapid breathing," 1896, from tachy- "swift" + -pnea, from pnein "to breathe" (see pneuma). Related: Tachypneic.
tacit (adj.): c. 1600, "silent, unspoken," from French tacite and directly from Latin tacitus "that is passed over in silence, done without words, assumed as a matter of course, silent," past participle of tacere "be silent, not speak," from suffixed form of PIE root *tak- "to be silent" (source also of Gothic þahan, Old Norse þegja "to be silent," Old Norse þagna "to grow dumb," Old Saxon thagian, Old High German dagen "to be silent"). The musical instruction tacet is the 3rd person present singular of the Latin verb. Related: Tacitly.