Online Etymology Dictionary

gizmo (n.): 1942, "Marine and Navy usage for any old thing you can't put a name to" ["Life" magazine, July 30, 1945], of unknown origin, perhaps a made-up word. Compare gadget, thingamajig.
harmonica (n.): 1762, coined by Ben Franklin as the name for a glass harmonica, from Latin fem. of harmonicus (see harmonic); modern sense of "reeded mouth organ" is 1873, American English, earlier harmonicon (1825).
Leonard: masc. proper name, from French Léonard, Old French Leonard, from German Leonhard, from Old High German *Lewenhart, literally "strong as a lion," from lewo (from Latin Leo, see lion) + hart "hard" (see hard (adj.)).
malapropism (n.): 1826, from Mrs. Malaprop, character in Sheridan's play "The Rivals" (1775), noted for her ridiculous misuse of large words (such as "contagious countries" for "contiguous countries"), her name coined from malapropos.
Eleanor: also Elinor, from Provençal Ailenor, a variant of Leonore, introduced in England by Eleanor of Aquitaine (1122-1204), wife of Henry II. The Old French form of the name was Elienor.
Bar Mitzvah: 1861, in Judaism, "male person who has completed his 13th year and thus reached the age of religious responsibility," from Hebrew, literally "son of command." As a name for the ceremony itself, by 1941.
Basil: masc. proper name, from Latin Basilius, from Greek Basileios "kingly, royal," from basileus "king," which is of unknown origin, possibly from a language of Asia Minor (compare Lydian battos "king").
bauxite (n.): 1861, clayey mineral containing aluminum, from French bauxite (1821), from Les Baux, near Soles, where it was first found. The place name is from Provençal Li Baus, literally "the precipices."
yogh (n.): Middle English letter (Ȝ), c. 1300; see Y. The name probably is identical with yoke (Middle English yogh) and so called because yoke began with a yogh.
Zion: late Old English Sion, from Greek Seon, from Hebrew Tsiyon, name of a Canaanite hill fortress in Jerusalem captured by David and called in the Bible "City of David." It became the center of Jewish life and worship.
zipper (n.): 1925, probably an agent noun from zip (v.1). The trademark taken out on the name that year applied to a boot with zippers, not to the "lightning fastener" itself, which was so called by 1927.
Vespa (n.): 1950, proprietary name of an Italian make of motor scooter, first produced 1946, from Italian, literally "wasp," from Latin vespa (see wasp). Rival brand was Lambretta.
Emmanuel: masc. personal name, from Greek form of Hebrew 'Immanu'el, literally "God is with us," from 'immanu "with us," from 'im "with," + first person plural pronominal suffix, + El "God."
emmet (n.): "ant," from Old English æmete (see ant), surviving as a dialect word in parts of England; also, according to OED, in Cornwall a colloquial name for holiday tourists.
emu (n.): large Australian three-toed bird, 1610s, probably from Portuguese ema "crane, ostrich" (which is of unknown origin), perhaps based on a folk-etymology of a native name.
caribou (n.): also cariboo, 1660s, from Canadian French caribou, from Micmac (Algonquian) kaleboo or a related Algonquian name, literally "pawer, scratcher," from its kicking snow aside to feed on moss and grass.
Casanova (n.): "man of carnal adventures, connoisseur of seduction," 1888, from Giacomo Girolamo Casanova de Seignalt (1725-1798), the infamous debaucher. His name could be Englished as Jacob Jerome Newhouse, which is somewhat less romantic.
Adonis (n.): "a beau," 1620s, from Greek Adonis, name of the youth beloved by Aphrodite, from Phoenician adon "lord," probably originally "ruler," from base a-d-n "to judge, rule." Adonai is the Hebrew cognate.
Ophelia: fem. proper name, from Greek opheleia "help, aid," from ophelein "to help, aid, assist," ophelos "advantage, help," from PIE root *obhel- "to avail" (source also of Greek ophelos "advantage," Armenian avelum "increase, abound").
Manchu: 1650s, member of Tungusic race of Manchuria which conquered China in 1644 and remained its ruling class until the Revolution of 1912. From Manchu, literally "pure," name of the tribe descended from the Nu-chen Tartars.
Mao (adj.): "simple style of clothing based on dress in Communist China," 1967, from French, from name of Mao Tse-tung (1893-1976), Chinese communist leader. Related: Maoism.
Nemean (adj.): 1580s, "pertaining to Nemea," a wooded valley in Argolis, especially in reference to the lion there, said to have been killed by Herakles. The place name is from Greek nemos "grove."
Nereid: "sea-nymph," 1510s, from Greek Nereis (genitive Nereidos), daughter of the ancient sea-god Nereus, whose name is related to naros "flowing, liquid, I flow" (see naiad).
Newspeak (n.): name of the artificial language of official communication in George Orwell's novel "Nineteen Eighty-Four," 1949, from new (adj.) + speak (n.). Frequently applied to what is perceived as propagandistic warped English.
redcap (n.): "porter at a railroad station," 1914, American English, from red (adj.1) + cap (n.). Earlier it was the name of the goldfinch, a type of hen, and a long-toothed spectre in Scottish castles.
teak (n.): type of large East Indian tree yielding dark, heavy wood, 1690s, from Portuguese teca, from Malayam tekka, corresponding to Tamil tekku, Telugu teku, Kanarese tegu "the teak tree." The Hindi name is sagwan, sagun.
technicolor (n.): "vivid color," 1946, earlier as a trademark name (Technicolor, registered in U.S. 1917) for a process of making color movies, from technical + color (n.). As an adjective from 1940.
Orkney: name of a group of islands off the north coast of Scotland, from Old Norse Orkney-jar "Seal Islands," from orkn "seal," probably imitative of its bark. Related: Orkneyman.
paramecium (n.): 1752, Modern Latin Paramecium, the genus name, coined from Greek paramekes "oblong, oval," from para- "on one side" (see para- (1)) + mekos "length," related to makros "long" (see macro-).
Parmesan (n.): type of dry, hard cheese, 1550s, from Italian Parmegiano "of Parma," from Parma, city in northern Italy, one of the places where the cheese is made. Full form parmeson chese is recorded from 1510s. The place name ultimately is Etruscan.
Passamaquoddy: Indian tribe of southeast Maine, from Micmac, literally "place where pollack are plentiful," or else, if it originally is a tribal name, "those of the place of many pollack."
Beatrice: fem. proper name, from French Béatrice, from Latin beatrix, fem. of beatricem "who makes happy," from beatus "happy, blessed," past participle of beare "make happy, bless" (see beatitude).
vulcanize (v.): 1827, "to put into flames," from Vulcan (q.v.), name of the Roman god of fire, + -ize. As a treatment for rubber, first recorded 1846. Related: Vulcanized; vulcanizing.
cayenne (n.): "pungent dried pepper," 1756, from Tupi (Brazil) kyynha "capsicum," mistakenly associated with town of Cayenne in French Guyana. The town name is the French form of Guyana.
cellophane (n.): 1912, trademark name for a flexible, transparent product made from regenerated cellulose, coined by the inventor, Swiss chemist Jacques E. Brandenberger (1872-1954), probably from cellulose + connective o + -phane.
Vietnam: country in Southeast Asia, from Vietnamese Viet, the people's name + nam "south." Division into North and South lasted from 1954 to 1976. Vietnam War attested by 1963.
chanticleer (n.): "a cock," c. 1300, from Old French Chantecler "sing-loud" (Modern French Chanteclair), name of the cock in medieval stories of Reynard the Fox; from chanter "to sing" (see chant (v.)) + cler (see clear (adj.)).
Chardonnay (n.): type of wine, 1907, from French chardonnay, originally the type of grape used to make the wine, supposedly named for the town of Chardonnay, Saône-et-Loire, in eastern France. The name is said to be from Latin Cardonnacum.
will-o'-the-wisp (n.): 1660s, earlier Will with the wisp (c. 1600), from the masc. proper name Will + wisp "bundle of hay or straw used as a torch." Compare Jack o'lantern.
Agamemnon: king of Mycenae, leader of the Greeks in the Trojan War, his name perhaps represents Greek Aga-medmon, literally "ruling mightily," from agan "very much" + medon "ruler" (see meditation).
Airedale: type of terrier, 1880, named for Airedale, a district in West Riding, Yorkshire.
Name registered by Kennel Club (1886), for earlier Bingley (where first bred), or broken-haired terrier. [Weekley]
Enoch: masc. proper name, in Old Testament eldest son of Cain, father of Methuselah, from Latin Enoch, from Greek Enokh, from Hebrew Hanokh, literally "dedicated, consecrated," from hanakh "he dedicated," whence also Hanukkah. Related: Enochian.
Enos: masc. proper name, in Old Testament the son of Seth, from Greek Enos, from Hebrew Enosh, literally "man" (compare nashim "women," Arabic ins "men, people").
Alcoran (n.): older form of Koran, mid-14c., from Old French alcoran, from Arabic al-quran "the Koran" (see Koran), with the definite article (al-) taken as part of the name.
Alethea: fem. proper name, from Greek aletheia "truth, truthfulness," from alethes "true," literally "not concealing," from privative prefix a- "not" (see a- (3)) + lethe "forgetfulness, oblivion" (see latent).
Algernon: masc. proper name, literally "with mustaches," from Old French als gernons, from a les "to the, with the" + gernon, variant of grenon "mustache," from Vulgar Latin *granonem, from a Germanic source (compare Old English granu "mustache").
Allen: masc. proper name, variant of Alan (q.v.). In reference to wrench, key, screw, etc. with hexagonal socket or head, 1913, from the Allen Manufacturing Company of Hartford, Connecticut, U.S.
digitalis (n.): 1660s, Modern Latin translation of German fingerhut, the German name of "foxglove," literally "thimble." Named by Fuchs (1542), and so called for its shape. The medicine (originally extracted from the plant) is so called from 1799.
grackle (n.): 1772, gracule, from genus name Gracula, Modern Latin use of fem. of Latin graculus "jackdaw, European crow," perhaps of imitative origin (compare crow (n.), crane (n.)). The Englished form of the word is attested from 1782.
Henley: town on the Thames in Oxfordshire, site of annual regatta since 1839. The name is Old English hean-leage "(settlement) at or by the high wood."