Online Etymology Dictionary

top-hat (n.): also tophat, 1875, from top (n.1) + hat.
top-heavy (adj.): 1530s, from top (n.1) + heavy (adj.).
top-notch (adj.): also top notch, 1848, from top (adj.) + notch (n.). Figurative of the "highest point" of something, but the exact mechanical image is uncertain.
top-sider (n.): kind of casual shoe, 1937, from topside in nautical sense of "upper deck of a ship," where the rubber soles would provide good grip; from top (n.1) + side (n.).
topaz (n.): colored crystalline gem, late 13c., from Old French topace (11c.), from Latin topazus (source also of Spanish topacio, Italian topazio), from Greek topazos, topazion, of obscure origin. Pliny says it was named for a remote island in the Red or Arabian Sea, where it was mined, the island so named for being hard to find (from Greek topazein "to divine, to try to locate"); but this might be folk etymology, and instead the word might be from the root of Sanskrit tapas "heat, fire." In the Middle Ages used for almost any yellow stone. To the Greeks and Romans, possibly yellow olivine or yellow sapphire. In modern science, fluo-silicate of aluminum. As a color name from 1908.
tope (v.): "to drink heavily," 1650s, of unknown origin, perhaps ultimately from Italian toppa "done!" a word signifying acceptance of a bet.
Topeka: city in Kansas, U.S.A., from Kansa (Siouan), literally "a good place to dig potatoes;"from /do/ "wild potato" + /ppi/ "good" + /ke/ "to dig."
toper (n.): "heavy drinker," 1670s, agent noun from tope (v.).
Tophet: place near Jerusalem, where, according to the Old Testament, idolatrous Jews made human sacrifice to strange gods; later symbolic of the torments of Hell.
topiary (adj.): 1590s, from Latin topiarius "of or pertaining to ornamental gardening," as a noun, "ornamental gardening, landscape gardening," also "an ornamental gardener," from topia "ornamental gardening," from Greek topia, plural of topion, originally "a field," diminutive of topos "place" (see topos). The noun is first recorded 1906, from the adjective.
topic (n.): 1630s, "a class of considerations from which probable arguments can be drawn," singular form of "Topics" (1560s), the name of a work by Aristotle on logical and rhetorical generalities, from Latin Topica, from Greek Ta Topika, literally "matters concerning topoi," "commonplaces," neuter plural of noun use of topikos "pertaining to a common place, of a place, local," from topos "place" (see topos). The meaning "matter treated in speech or writing, subject, theme" is first recorded 1720.
topical (adj.): 1580s, "pertaining to a place;" see topic + -al (1). Medical sense "applied to a particular part of the body" is from c. 1600. Meaning "of or pertaining to topics of the day" is from 1873. Related: Topically.
topknot (n.): 1680s, "a bow;" 1700, "tuft of hair on the head," from top (adj.) + knot (n.).
topless (adj.): of women, "bare-breasted," 1966, from top (n.1) + -less. Earlier it was used of men's bathing suits (1937) and women's (1964). Earliest sense is "without a visible summit; immeasurably high" (1580s).
topography (n.): early 15c., "description of a place," from Late Latin topographia, from Greek topographia "a description of a place," from topos "place" (see topos) + -graphia (see -graphy). Meaning "collective features of a region" is from 1847. Related: Topographic; topographical; topographically.
topology (n.): 1650s, "study of the locations where plants are found," from topo-, comb. form of Greek topos "place" (see topos) + -logy. Related: Topological.
toponym (n.): 1939, "place name," from comb. form of Greek topos "place" (see topos) + -onym "name" (see name (n.)). Toponymy "study of place names" is from 1876. Related: Toponymic; toponymics.
topos (n.): "literary theme," 1948, from Greek topos, literally "place."
topper (n.): "the best (of anything)," 1709, originally slang, agent noun from top (v.).
topping (n.): "an act of putting a top on," c. 1500, verbal noun from top (v.). Meaning "an act of cutting the top off" is from 1510s. Meaning "top layer of a food" is from 1839,
topple (v.): 1580s, "tumble down, fall headfirst," earlier "tumble or roll about" (1540s), from top (v.) "to tip" + frequentative suffix -le. Transitive sense also is from 1590s. Related: Toppled; toppling.
tops (n.): "the best," 1935, American English colloquial, from top (n.1).
topsoil (n.): also top-soil, 1789, from top (adj.) + soil (n.).
Topsy: slave-girl character in "Uncle Tom's Cabin" (1852), immortal in cliche for her response to a question about her origin put to her by the pious Northern abolitionist Miss Ophelia:
"Have you ever heard anything about God, Topsy?"
The child looked bewildered, but grinned, as usual.
"Do you know who made you?"
"Nobody as I knows on," said the child, with a short laugh.
The idea appeared to amuse her considerably; for her eyes twinkled, and she added--
"I spect I grow'd. Don't think nobody never made me."
In addition to being often misquoted by the addition of a "just" (or "jes'"), the line is sometimes used inappropriately in 20c. writing to indicate something that got large without anyone intending it to.
topsy-turvy (adv.): 1520s, "but prob. in popular use from an earlier period" [OED]; compare top over terve "to fall over" (mid-15c.); likely from tops, plural of top (n.1) "highest point" + obsolete terve "turn upside down, topple over," from Old English tearflian "to roll over, overturn," from Proto-Germanic *terbanan (source also of Old High German zerben "to turn round"). Century Dictionary calls it "A word which, owing to its popular nature, its alliterative type, and to ignorance of its origin, leading to various perversions made to suggest some plausible origin, has undergone, besides the usual variations of spelling, extraordinary modifications of form." It lists 31 variations. As an adjective from 1610s.
toque (n.): kind of round hat, c. 1500, from Middle French toque (15c.), from Spanish toca "woman's headdress," possibly from Arabic *taqa, from Old Persian taq "veil, shawl."
tor (n.): "high, rocky hill," Old English torr "rock, crag;" said to be a different word than torr "tower." Obviously cognate with Gaelic torr "lofty hill, mound," Old Welsh twrr "heap, pile;" and perhaps ultimately with Latin turris "high structure" (see tower (n.)). But sources disagree on whether the Celts borrowed it from the Anglo-Saxons or the other way round.
Torah (n.): "the Pentateuch," 1570s, from Hebrew torah, literally "instruction, law," verbal noun from horah "he taught, showed."
torch (n.): mid-13c., from Old French torche "torch," also "handful of straw" (for wiping or cleaning, hence French torcher "to wipe, wipe down"), originally "twisted thing," then "torch formed of twisted tow dipped in wax," probably from Vulgar Latin *torca, alteration of Late Latin torqua, from Latin torquere "to twist" (see torque (n.)).

In Britain, also applied to the battery-driven version (in U.S., a flashlight). To pass the torch is an ancient metaphor from the Greek torch-races (lampadedromia) where the goal was to reach the finish line with the torch still burning. Torch-bearer "leader of a cause" is from 1530s. Torch song is 1927 ("My Melancholy Baby," performed by Tommy Lyman, is said to have been the first so called), from carry a torch "suffer an unrequited love" (also 1927), Broadway slang, but the sense is obscure.
torch (v.): 1819, "illuminate with a torch," from torch (n.). Meaning "set fire to" is from 1931. Related: Torched; torching.
torcher (n.): "torch-carrier," c. 1600; see torch (n.). Meaning "torch singer" attested by 1940.
torchiere (n.): also torchere, "large, decorated candelabrum," 1910, from French torchère, from torche (see torch (n.)).
torchlight (n.): early 15c., from torch (n.) + light (n.).
toreador (n.): "bullfighter on horseback" (as opposed to a torero, who kills on foot), 1610s, from Spanish toreador, from torear "to participate in a bullfight," from toro "bull," from Latin taurus (see Taurus).
A toreador is, or rather was, a gentleman who killed bulls for his own amusement on horseback and with the spear. He was a sportsman, and his sport was as manly and respectable as pig-sticking. A professional fighter who performs in a ring and for money is a torero. ["Saturday Review," Jan. 22, 1887]
Tori: fem. proper name, originally short for Victoria.
toric (adj.): 1888, from torus + -ic.
torii (n.): singular and plural, "gateway to a Shinto temple," Japanese, according to OED from tori "bird" + i "to sit, to perch."
torment (n.): c. 1300, "the inflicting of torture," also "state of great suffering, pain, distress," from Old French torment "torture, pain, anguish, suffering distress" (11c., Modern French tourment), from Latin tormentum "twisted cord, sling; clothes-press; instrument for hurling stones," also "instrument of torture, a rack," figuratively "anguish, pain, torment," from torquere "to twist" (see torque (n.)).
torment (v.): c. 1300, "inflict torture on, distress," from Old French tormenter "torture, torment, oppress, agitate" (12c.), from Medieval Latin tormentare "to torment, to twist," from Latin tormentum (see torment (n.)). Related: Tormented; tormenting.
tormentor (n.): c. 1300, from Anglo-French tormentour, Old French tormenteor "torturer," agent noun from tormenter "to torture" (see torment (v.)).
torn: past participle of tear (v.); from Old English getoren.
tornado (n.): 1550s, ternado, navigator's word for violent windy thunderstorm in the tropical Atlantic, probably a mangled borrowing from Spanish tronada "thunderstorm," from tronar "to thunder," from Latin tonare "to thunder" (see thunder (n.)). Also in 17c. spelled tornatho, tornathe, turnado; modern spelling by 1620s. Metathesis of -o- and -r- in modern spelling influenced by Spanish tornar "to twist, turn," from Latin tornare "to turn." Meaning "extremely violent whirlwind" is first found 1620s; specifically "destructive rotary funnel cloud" (especially in the U.S. Midwest) from 1849. Related: Tornadic.
toro (n.): "bull," 1650s, from Spanish toro "bull," from Latin taurus (see steer (n.)).
Toronto: city in Ontario, Canada, founded 1793 as York, renamed 1834 for a native village that appears on a 1656 map as Tarantou, from an Iroquoian source, original form and sense unknown; perhaps taron-to-hen "wood in the water," or Huron deondo "meeting place."
torpedo (n.): 1520s, "electric ray" (flat fish that produces an electric charge to stun prey or for defense), from Latin torpedo "electric ray," originally "numbness, sluggishness" (the fish so called from the effect of being jolted by the ray's electric discharges), from torpere "be numb" (see torpor).
Torpedo. A fish which while alive, if touched even with a long stick, benumbs the hand that so touches it, but when dead is eaten safely. [Johnson]
The sense of "explosive device used to blow up enemy ships" is first recorded 1776, as a floating mine; the self-propelled version is from c. 1900. Related: Torpedic.
torpedo (v.): "destroy or sink (a ship) by a torpedo," 1874, from torpedo (n.). Also used late 19c. of blowing open oil wells. Figurative sense attested from 1895. Related: Torpedoed; torpedoing.
torpid (adj.): 1610s, "benumbed, without feeling or power," from Latin torpidus "benumbed, stupefied," from torpere "be numb or stiff" (see torpor). Figurative sense of "sluggish, dull, apathetic" is from 1650s. Related: Torpidly; torpidness.
torpidity (n.): 1610s; see torpid + -ity.
torpor (n.): "lethargy, listlessness," c. 1600, from Latin torpor "numbness, sluggishness," from torpere "be numb, be inactive, be dull," from PIE root *ster- (1) "stiff, rigid, firm, strong" (source also of Old Church Slavonic trupeti, Lithuanian tirpstu "to become rigid;" Greek stereos "solid;" Old English steorfan "to die;" see stereo-).
torque (n.): "rotating force," 1882, from Latin torquere "to twist, turn, turn about, twist awry, distort, torture," from PIE *torkw-eyo-, causative of *terkw- "to twist" (see thwart (adv.)). The word also is used (since 1834) by antiquarians and others as a term for the twisted metal necklace worn anciently by Gauls, Britons, Germans, etc., from Latin torques "collar of twisted metal," from torquere. Earlier it had been called in English torques (1690s). Torque-wrench is from 1941.