Online Etymology Dictionary

temperance (n.): mid-14c., "self-restraint, moderation," from Anglo-French temperaunce (mid-13c.), from Latin temperantia "moderation, sobriety, discretion, self-control," from temperans, present participle of temperare "to moderate" (see temper (v.)). Latin temperantia was used by Cicero to translate Greek sophrosyne "moderation." In English, temperance was used to render Latin continentia or abstinentia, specifically in reference to drinking alcohol and eating; hence by early 1800s it had come to mean "abstinence from alcoholic drink."
temperate (adj.): late 14c., of persons, "modest, forbearing, self-restrained, not swayed by passion;" of climates or seasons, "not liable to excessive heat or cold," from Latin temperatus "restrained, regulated, limited, moderate, sober, calm, steady," from past participle of temperare "to moderate, regulate" (see temper (v.)). Related: Temperately; temperateness. Temperate zone is attested from 1550s.
temperature (n.): mid-15c., "fact of being tempered, proper proportion;" 1530s, "character or nature of a substance," from Latin temperatura "a tempering, moderation," from temperatus, past participle of temperare "to mix in due proportion, modify, blend; restrain oneself" (see temper (v.)). Sense of "degree of heat or cold" first recorded 1670 (Boyle), from Latin temperatura, used in this sense by Galileo. Meaning "fever, high temperature" is attested from 1898.
tempered (adj.): 1650s, "brought to desired hardness" (of metals, especially steel), past participle adjective from temper (v.). Meaning "toned down by admixture" is from 1650s; of music or musical instruments, "tuned," from 1727.
tempest (n.): "violent storm," late 13c., from Old French tempeste "storm; commotion, battle; epidemic, plague" (11c.), from Vulgar Latin *tempesta, from Latin tempestas "a storm, commotion; weather, season; occasion, time," related to tempus "time, season" (see temporal).

Latin sense evolution is from "period of time" to "period of weather," to "bad weather" to "storm." Words for "weather" originally were words for "time" in languages from Russia to Brittany. Figurative sense of "violent commotion" in English is recorded from early 14c. Tempest in a teapot attested from 1818; the image in other forms is older, such as storm in a creambowl (1670s).
tempestuous (adj.): late 14c., from Late Latin tempestuosus "stormy, turbulent," from Latin tempestas, tempestus "storm, commotion; weather, season; occasion, time," related to tempus "time, season" (see temporal). For sense development, see tempest. The figurative sense is older in English; literal sense is from c. 1500. Related: Tempestuously; tempestuousness.
Templar (n.): late 13c., from Anglo-French templer, Old French templier (c. 1200), from Medieval Latin templaris (mid-12c.), member of the medieval religious/military order known as Knights Templars (c.1118-1312), so called because they had headquarters in a building near Solomon's Temple in Jerusalem (see temple (n.1)). Their distinguishing garb was a white mantle with a red cross.
template (n.): 1670s, templet "horizontal piece under a girder or beam," probably from French templet "weaver's stretcher," diminutive of temple, which meant the same thing, from Latin templum "plank, rafter," also "consecrated place" (see temple (n.1)).

The meaning "pattern or gauge for shaping a piece of work" is first recorded 1819 in this form, earlier temple (1680s); the form was altered mid-19c., probably influenced by plate [Barnhart], but the pronunciation did not begin to shift until more recently (templet is still the primary entry for the word in Century Dictionary).
temple (n.1): "building for worship, edifice dedicated to the service of a deity or deities," Old English tempel, from Latin templum "piece of ground consecrated for the taking of auspices, building for worship of a god," of uncertain signification.

Commonly referred to PIE root *tem- "to cut" (see tome), on notion of "place reserved or cut out" [Watkins], or to root *temp- "to stretch" [Klein, de Vaan], on notion of "cleared (measured) space in front of an altar" (see tenet and temple (n.2)), the notion being perhaps the "stretched" string that marks off the ground. Compare Greek temenos "sacred area around a temple," literally "place cut off," from stem of temnein "to cut." Figurative sense of "any place regarded as occupied by divine presence" was in Old English. Applied to Jewish synagogues from 1590s.
temple (n.2): "flattened area on either side of the forehead," mid-14c., from Old French temple "side of the forehead" (11c.), from Vulgar Latin *tempula (plural taken as fem. singular), from Latin tempora, plural of tempus (genitive temporis) "side of the forehead," generally accepted as having originally meant "the thin stretch of skin at the side of the forehead" and being from PIE *temp- "to stretch," an extension of the root *ten- "to stretch" (see tenet). The sense development would be from "stretchings" to "stretched skin."

A similar notion seems to be at work in Old English ðunwange, Old Norse þunn-vangi, Old High German dunwangi "temple," literally "thin cheek." The less-likely guess is that it is associated with tempus span "timely space" (for a mortal blow with a sword).
tempo (n.): "relative speed of a piece of music," 1724, from Italian tempo, literally "time" (plural tempi), from Latin tempus "time, season, portion of time" (see temporal). Extended (non-musical) senses by 1898.
temporal (adj.): late 14c., "worldly, secular;" also "terrestrial, earthly; temporary, lasting only for a time," from Old French temporal "earthly," and directly from Latin temporalis "of time, denoting time; but for a time, temporary," from tempus (genitive temporis) "time, season, moment, proper time or season," from Proto-Italic *tempos- "stretch, measure," which according to de Vaan is from PIE *temp-os "stretched," from root *ten- "to stretch" (see tenet), the notion being "stretch of time." Related: Temporally.
temporality (n.): late 14c., "temporal power," from Late Latin temporalitas, from temporalis "of a time, but for a time" (see temporal).
temporary (adj.): "lasting only for a time," 1540s, from Latin temporarius "of seasonal character, lasting a short time," from tempus (genitive temporis) "time, season" (see temporal, late 14c., which was the earlier word for "lasting but for a time"). The noun meaning "person employed only for a time" is recorded from 1848. Related: Temporarily; temporariness.
temporize (v.): "to comply with the times; to yield ostensibly to the current of opinion or circumstances," 1550s (implied in temporizer), from Middle French temporiser "to pass one's time, wait one's time" (14c.), from Medieval Latin temporizare "pass time," perhaps via Vulgar Latin *temporare "to delay," from Latin tempus (genitive temporis) "time" (see temporal). Related: Temporized; temporizing.
tempt (v.): c. 1200, of the devil, flesh, etc., "draw or entice to evil or sin, lure (someone) from God's law; be alluring or seductive," from Old French tempter (12c.), from Latin temptare "to feel, try out, attempt to influence, test," a variant of tentare "handle, touch, try, test." The Latin alteration is "explainable only as an ancient error due to some confusion" [Century Dictionary]. From late 14c. as "to provoke, defy" (God, fate, etc.). Related: Tempted; tempting.
temptation (n.): c. 1200, "act of enticing someone to sin," also "an experience or state of being tempted," from Old French temptacion (12c., Modern French tentation), from Latin temptationem (nominative temptatio), noun of action from past participle stem of temptare "to feel, try out" (see tempt). Meaning "that which tempts a person (to sin)" is from c. 1500.
tempter (n.): mid-14c., "one who solicits to sin; that which entices to evil" (originally especially the devil), from Middle French tempteur (14c.), Old French *tempteor, from Latin temptatorem, agent noun from temptare "to feel, try out" (see tempt).
tempting (adj.): "inviting, seductive, alluring," 1590s, present participle adjective from tempt (v.). Related: Temptingly.
temptress (n.): 1590s, from tempter + -ess.
tempura (n.): 1920, from Japanese, probably from Portuguese tempero "seasoning."
ten (n., adj.): Old English ten (Mercian), tien (West Saxon), adjective and noun, from Proto-Germanic *tehun (source also of Old Saxon tehan, Old Norse tiu, Danish ti, Old Frisian tian, Old Dutch ten, Dutch tien, Old High German zehan, German zehn, Gothic taihun "ten").

The Germanic words are from PIE *dekm "ten" (source also of Sanskrit dasa, Avestan dasa, Armenian tasn, Greek deka, Latin decem (source of Spanish diez, French dix), Old Church Slavonic deseti, Lithuanian desimt, Old Irish deich, Breton dek, Welsh deg, Albanian djetu "ten").

Meaning "ten o'clock" is from 1712. Tenner "ten-pound note" is slang first recorded 1861; as "ten-dollar bill," 1887 (ten-spot in this sense dates from 1848). The Texan's exaggerated ten-gallon hat is from 1919. The ten-foot pole that you wouldn't touch something with (1909) was originally a 40-foot pole; the notion is of keeping one's distance, the same as in the advice to use a long spoon when you dine with the devil. Ten-four "I understand, message received," is attested in popular jargon from 1962, from use in CB and police radio 10-code (in use in U.S. by 1950).
tenable (adj.): "capable of being held or maintained," 1570s, from Middle French tenable, from Old French (12c.), from tenir "to hold," from Latin tenere "to hold, keep" (see tenet).
tenacious (adj.): c. 1600, from Latin stem of tenacity + -ous. Related: Tenaciously; tenaciousness.
tenacity (n.): early 15c., from Middle French ténacité (14c.) and directly from Latin tenacitas "an act of holding fast," from tenax (genitive tenacis) "holding fast, gripping, clingy; firm, steadfast," from tenere "to hold" (see tenet).
tenant (n.): early 14c., "person who holds lands by title or by lease," from Anglo-French tenaunt (late 13c.), Old French tenant "possessor; feudal tenant" (12c.), noun use of present participle of tenir "to hold," from Latin tenere "hold, keep, grasp" (see tenet). Related: Tenancy. Tenant-farmer attested from 1748.
tend (v.1): "to incline, to move in a certain direction," early 14c., from Old French tendre "stretch out, hold forth, hand over, offer" (11c.), from Latin tendere "to stretch, extend, make tense; aim, direct; direct oneself, hold a course" (see tenet).
tend (v.2): "attend to," c. 1200, a shortening of Middle English atenden (see attend).
tendency (n.): 1620s, from Medieval Latin tendentia "inclination, leaning," from Latin tendens, present participle of tendere "to stretch, extend, aim" (see tenet). Earlier in same sense was tendaunce (mid-15c.), from Old French tendance.
tendential (adj.): 1877, from Latin stem of tendency + -al (1). Related: Tendentially.
Tendenziöse is a term that has become very common in Germany to describe the Tübingen criticism, and has arisen from the lengths to which theologians of this school have shown themselves ready to go, to establish the hypothesis that the New Testament writings arose out of conflicting tendencies in the early church and efforts to bring about compromises between these factions. The word has been transferred in the translation under the form "tendential." [translator's preface to "Hermeneutics of the New Testament" by Dr. Abraham Immer, translated by Albert H. Newman, 1877]
tendentious (adj.): "having a definite purpose," 1871, formed after or from German tendenziös, from Tendenz "tendency," from Medieval Latin tendentia (see tendency).
tender (adj.): "soft, easily injured," early 13c., from Old French tendre "soft, delicate; young" (11c.), from Latin tenerem (nominative tener) "soft, delicate; of tender age, youthful," from a derivative of PIE root *ten- "stretch" (see tenet), on the notion of "stretched," hence "thin," hence "weak" or "young." Compare Sanskrit tarunah "young, tender," Greek teren "tender, delicate," Armenian t'arm "young, fresh, green."

Meaning "kind, affectionate, loving" first recorded early 14c. Meaning "having the delicacy of youth, immature" is attested in English from early 14c. Related: Tenderly; tenderness. Tender-hearted first recorded 1530s.
tender (n.1): "person who tends another," late 15c., probably an agent noun formed from Middle English tenden "attend to" (see tend (v.2)); later extended to locomotive engineers (1825) and barmen (1883). The meaning "small boat used to attend larger ones" first recorded 1670s.
tender (v.): "to offer formally," 1540s, from Middle French tendre "to offer, hold forth" (11c.), from Latin tendere "to stretch, extend" (see tenet). The retention of the ending of the French infinitive is unusual (see render (v.) for another example).
tender (n.2): "formal offer for acceptance," 1540s, from tender (v.). Specific sense of "money offered as payment" is from 1740, in legal tender "currency which by law must be accepted from a debtor" (see legal).
tenderfoot (n.): 1866, American English, originally of newcomers to ranching or mining districts, from tender (adj.) + foot (n.). The U.S. equivalent of what in Great Britain was generally called a greenhand. As a level in Boy Scouting, it is recorded from 1908.
Among the Indians, more than half of every sentence is expressed by signs. And miners illustrate their conversation by the various terms used in mining. I have always noticed how clearly these terms conveyed the idea sought. Awkwardness in comprehending this dialect easily reveals that the hearer bears the disgrace of being a "pilgrim," or a "tender-foot," as they style the new emigrant. ["A Year in Montana," "Atlantic Monthly," August 1866]
Tender-footed (adj.) "cautious", originally of horses, is recorded from 1680s; of persons from 1854.
tenderize (v.): 1733, from tender + -ize. Specifically of food, recorded by 1935, originally American English. Related: Tenderized; tenderizing.
tenderizer (n.): 1942, agent noun from tenderize.
tenderloin (n.): 1828, "tender part of a loin of pork or beef," from tender (adj.) + loin. The slang meaning "police district noted for vice" appeared first 1887 in New York, on the notion of the neighborhood of the chief theaters, restaurants, etc., being the "juciest cut" for graft and blackmail.
tendinitis (n.): 1900, from Medieval Latin tendinis, genitive of tendo (see tendon) + -itis "inflammation."
tendon (n.): 1540s, from Medieval Latin tendonem (nominative tendo), altered (by influence of Latin tendere "to stretch") from Late Latin tenon, from Greek tenon (genitive tenontos) "tendon, sinew," from PIE *ten-on- "something stretched," from root *ten- "to stretch" (see tenet).
tendonitis (n.): see tendinitis.
tendril (n.): "leafless plant-organ attaching to another for support," 1530s, from Middle French tendrillon "bud, shoot, cartilage," perhaps a diminutive of tendron "cartilage," from Old French tendre "soft" (see tender (adj.)), or else from Latin tendere "to stretch, extend" (see tender (v.)).
tenebrism (n.): 1959, with -ism + tenebroso (1886), in reference to 17c. Italian painters in the style of Caravaggio, from Italian tenebroso "dark," from Latin tenebrosus "dark, gloomy," from tenebrae "darkness" (see temerity).
tenebrous (adj.): "full of darkness," late 15c., from Old French tenebros "dark, gloomy" (11c., Modern French ténébreux), from Latin tenebrosus "dark," from tenebrae "darkness" (see temerity). Related: Tenebrosity.
tenement (n.): c. 1300, "holding of immovable property" (such as land or buildings,) from Anglo-French (late 13c.), Old French tenement "fief, land, possessions, property" (12c.), from Medieval Latin tenementum "a holding, fief" (11c.), from Latin tenere "to hold" (see tenet). The meaning "dwelling place, residence" is attested from early 15c.; tenement house "house broken up into apartments, usually in a poor section of a city" is first recorded 1858, American English, from tenement in an earlier sense (especially in Scotland) "large house constructed to be let to a number of tenants" (1690s).
tenesmus (n.): "a straining" (to void the contents of the bowels), 1520s, medical Latin, from Greek tenesmos "a straining," from teinein "to stretch" (see tenet).
tenet (n.): "principle, opinion, or dogma maintained as true by a person, sect, school, etc.," properly "a thing held (to be true)," early 15c., from Latin tenet "he holds," third person singular present indicative of tenere "to hold, grasp, keep, have possession, maintain," also "reach, gain, acquire, obtain; hold back, repress, restrain;" figuratively "hold in mind, take in, understand."

The Latin word is from PIE root *ten- "to stretch" (source also of Sanskrit tantram "loom," tanoti "stretches, lasts;" Persian tar "string;" Lithuanian tankus "compact," i.e. "tightened;" Greek teinein "to stretch," tasis "a stretching, tension," tenos "sinew," tetanos "stiff, rigid," tonos "string," hence "sound, pitch;" Latin tendere "to stretch," tenuis "thin, rare, fine;" Old Church Slavonic tento "cord;" Old English þynne "thin"). Connecting notion between "stretch" and "hold" is "cause to maintain." The modern sense is probably because tenet was used in Medieval Latin to introduce a statement of doctrine.
tenfold (adj.): Old English tienfeald; see ten + -fold. As an adverb in modern use from 1530s.
Tennessee: state and river, from Cherokee (Iroquoian) village name ta'nasi', of unknown origin. Related: Tennesseean.