Online Etymology Dictionary

tennis (n.): mid-14c., most likely from Anglo-French tenetz "hold! receive! take!," from Old French tenez, imperative of tenir "to hold, receive, take" (see tenet), which was used as a call from the server to his opponent. The original version of the game (a favorite sport of medieval French knights) was played by striking the ball with the palm of the hand, and in Old French was called la paulme, literally "the palm," but to an onlooker the service cry would naturally seem to identify the game. Century Dictionary says all of this is "purely imaginary."

The use of the word for the modern game is from 1874, short for lawn tennis, which originally was called sphairistike (1873), from Greek sphairistike (tekhne) "(skill) in playing at ball," from the root of sphere. It was invented, and named, by Maj. Walter C. Wingfield and first played at a garden party in Wales, inspired by the popularity of badminton.
The name 'sphairistike,' however, was impossible (if only because people would pronounce it as a word of three syllables to rhyme with 'pike') and it was soon rechristened. ["Times" of London, June 10, 1927]
Tennis-ball attested from mid-15c.; tennis-court from 1560s; tennis-elbow from 1883; tennis-shoes from 1887.
Tenochtitlan: former Aztec city, Nahuatl (Aztecan), literally "place of the nopal rock," from tetl "rock" + nuchtli "nopal," a species of cactus sacred to the sun god.
tenon (n.): projection inserted to make a joint, late 14c., from Middle French tenon "a tenon," from Old French tenir "to hold" (see tenet). As a verb from 1590s.
tenor (n.): c. 1300, "general meaning, prevailing course, purpose, drift," from Old French tenor "substance, contents, meaning, sense; tenor part in music" (13c. Modern French teneur), from Latin tenorem (nominative tenor) "a course," originally "continuance, uninterrupted course, a holding on," from tenere "to hold" (see tenet). The musical sense of "high male voice" is attested from late 14c. in English, so-called because the sustained melody (canto fermo) was carried by the tenor's part. Meaning "singer with a tenor voice" is from late 15c. As an adjective in this sense from 1520s.
tenpins (n.): c. 1600, from ten + plural of pin (n.). From the number of pins to be knocked down.
tense (adj.): "stretched tight," 1660s, from Latin tensus, past participle of tendere "to stretch, extend" (see tenet). Figurative sense of "in a state of nervous tension" is first recorded 1821. Related: Tensely; tenseness.
tense (n.): "form of a verb showing time of an action or state," early 14c., tens "time," also "tense of a verb" (late 14c.), from Old French tens "time, period of time, era; occasion, opportunity; weather" (11c., Modern French temps), from Latin tempus "a portion of time" (also source of Spanish tiempo, Italian tempo; see temporal).
tense (v.): "to make tense," 1670s, from tense (adj.); intransitive sense of "to become tense" (often tense up) is recorded from 1946. Related: Tensed; tensing.
tensile (adj.): 1620s, "stretchable," from Modern Latin tensilis "capable of being stretched," from Latin tensus, past participle of tendere "to stretch" (see tenet). Meaning "pertaining to tension" is from 1841.
tension (n.): 1530s, "a stretched condition," from Middle French tension (16c.) or directly from Latin tensionem (nominative tensio) "a stretching" (in Medieval Latin "a struggle, contest"), noun of state from tensus, past participle of tendere "to stretch," from PIE root *ten- "stretch" (see tenet). The sense of "nervous strain" is first recorded 1763. The meaning "stress along lines of electromotive force" (as in high-tension wires) is recorded from 1785.
tensor (n.): muscle that stretches or tightens a part, 1704, Modern Latin agent noun from tens-, past participle stem of Latin tendere "to stretch" (see tenet).
tent (n.): c. 1300, "portable shelter of skins or coarse cloth stretched over poles," from Old French tente "tent, hanging, tapestry" (12c.), from Medieval Latin tenta "a tent," literally "something stretched out," noun use of fem. singular of Latin tentus "stretched," variant past participle of tendere "to stretch" (see tenet). The notion is of "stretching" hides over a framework. Tent caterpillar first recorded 1854, so called from the tent-like silken webs in which they live gregariously.
tent (v.): "to camp in a tent," 1856, from tent (n.). Earlier "to pitch a tent" (1550s). Related: Tented; tenting.
tentacle (n.): 1762, from Modern Latin tentaculum, literally "feeler," from Latin tentare "to feel, try" + -culum, diminutive suffix (see -cule). Related: Tentacular.
tentative (adj.): 1580s, from Medieval Latin tentativus "trying, testing," from Latin tentatus, past participle of tentare "to feel, try." Related: Tentatively; tentativeness.
tenter (n.): c. 1300, "wooden framework for stretching cloth," of uncertain origin, probably via Old French (but the evolution of the ending is obscure), and ultimately from Latin tentorium "tent made of stretched skins," from tentus "stretched," variant past participle of tendere "to stretch" (see tenet).
tenterhooks (n.): plural of tenterhook (late 15c.), "one of the hooks that holds cloth on a tenter," from tenter + hook (n.). The figurative phrase on tenterhooks "in painful suspense" is from 1748; earlier to be on tenters (1530s).
tenth (adj.): mid-12c., tenðe; see ten + -th (1). Replacing Old English teoða (West Saxon), teiða (Northumbrian), which is preserved in tithe. Compare Old Saxon tehando, Old Frisian tegotha, Dutch tiende, Old High German zehanto, German zehnte, Gothic taihunda. As a noun from c. 1200.
tenuious (adj.): late 15c., from Latin tenuis "thin" (see tenuous) + -ous.
tenuous (adj.): 1590s, "thin, unsubstantial," irregularly formed from Latin tenuis "thin, drawn out, meager, slim, slender," figuratively "trifling, insignificant, poor, low in rank," from PIE root *ten- "to stretch" (source also of Sanskrit tanuh "thin," literally "stretched out;" see tenet) + -ous. The correct form with respect to the Latin is tenuious. The figurative sense of "having slight importance, not substantial" is found from 1817 in English. Related: Tenuously; tenuousness.
tenure (n.): early 15c., "holding of a tenement," from Anglo-French and Old French tenure "a tenure, estate in land" (13c.), from Old French tenir "to hold," from Vulgar Latin *tenire, from Latin tenere "to hold" (see tenet). The sense of "condition or fact of holding a status, position, or occupation" is first attested 1590s. Meaning "guaranteed tenure of office" (usually at a university or school) is recorded from 1957. Related: Tenured (1961).
teocalli (n.): place of worship of ancient Mexicans, 1570s, from American Spanish, from Nahuatl (Aztecan) teohcalli "temple, church," literally "god-house," from teotl "god" + calli "house."
teonanacatl (n.): native name for a hallucinogenic fungi (Psilocybe mexicana) found in Central America, 1875, from Nahuatl (Aztecan), from teotl "god" + nancatl "mushroom."
tepee (n.): 1743, ti pee, from Dakota (Siouan) thipi "dwelling, house."
tephromancy (n.): 1650s, "divination by means of ashes," from Modern Latin tephromantia, from comb. form of Greek tephra "ashes" + manteia "divination," from mantis "prophet" (see mania).
tepid (adj.): c. 1400, from Latin tepidus "lukewarm," from tepere "be moderately warm," from PIE root *tep- "to be hot" (source also of Sanskrit tapati "makes warm, heats, burns," tapas "heat, austerity;" Avestan tafnush "fever;" Old Church Slavonic topiti "to warm," teplu "warm;" Old Irish tene "fire;" Welsh tes "heat"). Related: Tepidly; tepidity.
tequila (n.): Mexican brandy, 1849 (from 1841 as vino de Tequila), from American Spanish tequila, from Tequila, name of a district in central Mexico noted for the fine quality of its tequila. Tequila sunrise is attested by 1965.
ter-: word-forming element meaning "thrice, three times," from Latin ter "thrice," from *tris-, from root of three. Compare Latin tertius "third."
tera-: prefix meaning "trillion," used in forming large units of measure (such as terabyte), officially adopted 1947, from Greek teras "marvel, monster" (see terato-).
terabyte (n.): by 1982, from tera- + byte.
terato-: before vowels terat-, word-forming element meaning "marvel, monster," from comb. form of Greek teras (genitive teratos) "marvel, sign, wonder, monster," from PIE *kewr-es-, from root *kwer- "to make, form" (source also of Sanskrit krta- "make, do, perform," Lithuanian keras "charm," Old Church Slavonic čaru "charm").
teratogen (n.): 1959, from terato- "marvel, monster" + -gen.
teratogenic (adj.): "causing the formation of monsters," 1873, from teratogeny + -ic; probably based on German teratogenic (by 1856).
teratogeny (n.): "the production of monsters," 1855, from terato- + -geny. Related: Teratogenesis.
teratology (n.): "study of marvels and monstrosities," 1842, from terato- + -logy. Earlier it meant "marvelous narrative" (1670s), from Greek teratologia "a telling of marvels." Related: Teratological; teratologist.
teratoscopy (n.): "augury from prodigies," 1660s; see terato- + -scopy.
terbium (n.): 1843, from Latinized form of Ytterby, Swedish town near the place where mineral containing the element was found (see Ytterbium). With metallic element ending -ium.
tercel (n.): "male falcon," late 14c., from Old French tercel (c. 1200), from Medieval Latin tertiolus, from Latin tertius "third, a third," from root of tres "three" (see three). Various theories as to why it is called this; one says it's because the males are a third smaller than the females, another because a third egg in the nest (smaller than the other two) is believed always to produce a male bird.
tercentenary (adj.): 1832, "pertaining to a period of 300 years," from ter- "three times" + centenary. As a noun from 1835. Related: Tercentennial (1862 as an adjective; 1872 as a noun).
terceroon (n.): offspring of a white and a mulatto, 1760, from Spanish *terceron, from tercero "a third (person)," from tercio "third," from Latin tertius "a third," from root of tres "three" (see three). So called from being third in descent from a Negro.
tercet (n.): "three successive lines rhyming together," 1590s, from Italian terzetto, diminutive of terzo "third," from Latin tertius (see third). Spelling influenced by French tercet, from the Italian.
terebinth (n.): Mediterranean tree, a member of the sumac family, late 14c., from Old French therebint (13c.), from Latin terebinthus (Pliny), from Greek terebinthos, earlier terminthos, probably from a non-Indo-European language (Klein suggests Creto-Minoic). The tree is the source of Chian turpentine. Related: Terebinthine; terebinthaceous.
tergiversate (v.): 1650s, back-formation from tergiversation, or else from Latin tergiversatus, past participle of tergiversari "be evasive," literally "to turn one's back." Related: Tergiversated; tergiversating.
tergiversation (n.): turning dishonestly from a straightforward action or statement; shifting, shuffling, equivocation, 1560s, from Latin tergiversationem (nominative tergiversatio) "a shifting, evasion, declining, refusing," from past participle stem of tergiversari "turn one's back on, evade," from tergum "the back" (of unknown origin) + versare "to spin, turn" (see versus).
teriyaki: 1962, from Japanese, from teri "gloss, luster" + yaki "roast."
term (n.): c. 1200, terme "limit in time, set or appointed period," from Old French terme "limit of time or place, date, appointed time, duration" (11c.), from Latin terminus "end, boundary line," in Medieval Latin "expression, definition," related to termen "boundary, end" (see terminus). Old English had termen "term, end," from Latin. Sense of "period of time during which something happens" first recorded c. 1300, especially of a school or law court session (mid-15c.).

The meaning "word or phrase used in a limited or precise sense" is first recorded late 14c., from Medieval Latin use of terminus to render Greek horos "boundary," employed in mathematics and logic. Hence in terms of "in the language or phraseology peculiar to." Meaning "completion of the period of pregnancy" is from 1844. Term-paper in U.S. educational sense is recorded from 1931.
term (v.): "to give a particular name to," 1550s, from term (n.). Related: Termed; terming.
termagant (n.): c. 1500, "violent, overbearing person" (especially of women), from Teruagant, Teruagaunt (c. 1200), name of a fictitious Muslim deity appearing in medieval morality plays, from Old French Tervagant, a proper name in Chanson de Roland (c. 1100), of uncertain origin. As an adjective from 1590s.
terminable (adj.): early 15c., from Latin stem of terminate (v.) + -able.
terminal (adj.): mid-15c., "relating to or marking boundaries," from Latin terminalis "pertaining to a boundary or end, final," from terminus "end, boundary line" (see terminus). Meaning "fatal" (terminal illness) is first recorded 1891. Sense of "situated at the extreme end" (of something) is from 1805. Slang meaning "extreme" first recorded 1983. Related: Termninally.