Online Etymology Dictionary

Greco-Roman (adj.): "of or pertaining to both Greek and Roman," by 1811; see Greco- + Roman (adj.).
Greece: c. 1300, from Latin Graecia; named for its inhabitants; see Greek. Earlier in English was Greklond (c. 1200). The Turkish name for the country, via Persian, is Yunanistan, literally "Land of the Ionians." Ionia also yielded the name for the country in Arabic and Hindi (Yunan).
greed (n.): "excessively eager desire to possess," c. 1600, a back-formation from greedy.
greedily (adv.): Old English grædiglice; see greedy + -ly (2).
greediness (n.): Old English grædignes; see greedy + -ness.
greedy (adj.): Old English grædig (West Saxon), gredig (Anglian) "voracious, hungry," also "covetous, eager to obtain," from Proto-Germanic *grædagaz (source also of Old Saxon gradag "greedy," Old Norse graðr "greed, hunger," Danish graadig, Dutch gretig, Old High German gratag "greedy," Gothic gredags "hungry"), from *græduz (source also of Gothic gredus "hunger," Old English grædum "eagerly"), possibly from PIE root *gher- (5) "to like, want" (source of Sanskrit grdh "to be greedy").

In Greek, the word was philargyros, literally "money-loving." A German word for it is habsüchtig, from haben "to have" + sucht "sickness, disease," with sense tending toward "passion for."
Greek (n.): Old English Grecas, Crecas (plural) "Greeks, inhabitants of Greece," early Germanic borrowing from Latin Graeci "the Hellenes," apparently from Greek Graikoi. Aristotle, who was the first to use Graikhos as equivalent to Hellenes ("Meteorologica" I.xiv), wrote that it was the name originally used by Illyrians for the Dorians in Epirus, from Graii, native name of the people of Epirus.

But a modern theory (put forth by German classical historian Georg Busolt, 1850-1920), derives it from Graikhos "inhabitant of Graia" (literally "gray," also "old, withered"), a town on the coast of Boeotia, which was the name given by the Romans to all Greeks, originally to the Greek colonists from Graia who helped found Cumae (9c. B.C.E.), the important city in southern Italy where the Latins first encountered Greeks. Under this theory, it was reborrowed in this general sense by the Greeks.

The Germanic languages originally borrowed the word with an initial "-k-" sound (compare Old High German Chrech, Gothic Kreks), which probably was their initial sound closest to the Latin "-g-" at the time; the word was later refashioned. From late 14c. as "the Greek language." Meaning "unintelligible speech, gibberish, any language of which one is ignorant" is from c. 1600. Meaning "member of a Greek-letter fraternity" is student slang, 1884.
It was subtle of God to learn Greek when he wished to become an author -- and not to learn it better. [Nietzsche, "Beyond Good and Evil," 1886]
Greek (adj.): late 14c., "of Greece or its people," from Greek (n.). Earlier Gregeis (c. 1200), from Old French Gregois; also Greekish (Old English Grecisc). From 1540s as "of the Greek language;" 1550s as "of the Eastern Church." From 1888 as "of Greek-letter fraternities." In venery, "anal," by 1970. Greek fire "inflammable substance invented 7c. by Callinicus of Heliopolis and used by the Byzantines (who in the Middle Ages were known as 'Greeks')" is from c. 1400, earlier Grickisce fure (c. 1200). Greek gift is from "Æneid," II.49: "timeo Danaos et dona ferentes."
green (adj.): Old English grene, Northumbrian groene "green, of the color of living plants," in reference to plants, "growing, living, vigorous," also figurative, of a plant, "freshly cut," of wood, "unseasoned" earlier groeni, from Proto-Germanic *gronja- (source also of Old Saxon grani, Old Frisian grene, Old Norse grænn, Danish grøn, Dutch groen, Old High German gruoni, German grün), from PIE root *ghre- "grow" (see grass), through sense of "color of growing plants."

From c. 1200 as "covered with grass or foliage." From early 14c. of fruit or vegetables, "unripe, immature;" and of persons, "of tender age, youthful, immature, inexperienced;" hence "gullible, immature with regard to judgment" (c. 1600). From mid-13c. in reference to the skin or complexion of one sick.

Green cheese originally was that which is new or fresh (late 14c.), later with reference to coloring; for the story told to children that the moon is made of it, see cheese (n.1). Green light in figurative sense of "permission" is from 1937 (Green and red as signals on railways first attested 1883, as nighttime substitutes for semaphore flags). Green thumb for "natural for gardening" is by 1938. Green beret originally "British commando" is from 1949. Greenroom "room for actors when not on stage" is from 1701; presumably a once-well-known one was painted green. The color of environmentalism since 1971.
green (v.): Old English grenian "to become green, flourish" (see green (adj.)). Compare Dutch groenen, German grünen, Old Norse grona. Meaning "to make green" is 1560s. Related: Greened; greening.
green (n.): late Old English, "green color or pigment, spectral color between blue and yellow;" also "a field, grassy place; green garments; green foliage," from green (adj.). Specific sense "piece of grassland in a village belonging to the community" is by late 15c. In golf, "the putting portion of the links" by 1849. Symbolic of inconstancy since late 14c., perhaps because in nature it changes or fades. Also symbolic of envy and jealousy since Middle English. Shakespeare's green-eyed monster of "Othello" sees all through eyes tinged with jealousy. "Greensleeves," ballad of an inconstant lady-love, is from 1570s. The color of the cloth in royal counting houses from late 14c., later the color of the cloth on gambling tables.
greenback (n.): "U.S. dollar bill," 1862, so called from the time of their introduction, from green (adj.) + back (n.); bank paper money printed in green ink had been called this since 1778 (as opposed to redbacks, etc.).
greenery (n.): "mass of green plants or foliage," 1797, from green (n.) + -ery. From 1836 as "place where plants are reared."
greengage (n.): type of plum, from green (adj.) + name of English botanist Sir William Gage (1657-1727) who first cultivated it in England c. 1725. In early 20c., rhyming slang for "stage."
greengrocer (n.): 1723, from green (n.) "vegetable" + grocer.
greenhead (n.): 1580s, "young, untrained intellect," from green (adj.) + head (n.). As a type of biting fly with a green-colored head, by 1837.
greenhorn (n.): mid-15c., "horn of an animal recently killed," also "young horned animal," from green (adj.) in sense of "new, fresh, recent" + horn (n.). Applied to new soldiers from c. 1650; extended to any inexperienced person by 1680s.
greenhouse (n.): also green-house, 1660s, from green (n.) + house (n.). Greenhouse effect attested from 1937.
greenish (adj.): late 14c., from green (adj.) + -ish.
Greenland: translating Old Norse Groenland, so named by its discoverer (986 C.E.) because "it would induce settlers to go there, if the land had a good name":
Hann gaf nafn landinu ok kallaði Groenland, ok kvað menn þat myndu fysa þangat farar, at landit ætti nafn gott. [Islendingabok, 1122-1133]
See green (adj.) + land (n.). Related: Greenlander; Greenlandish.
greenness (n.): Old English grennes "green color; quality of being green," in plural, "green things, plants;" see green (adj.) + -ness. Meaning "immaturity" is from early 15c. Walpole coined greenth (1753) in the same sense.
greens (n.): c. 1400, "vegetables;" 1690s, "freshly cut branches used for decoration," from green (n.). Meaning "ecology political party" first recorded 1978, from German die Grünen (West Germany), an outgrowth of Grüne Aktion Zukunft "Green Campaign for the Future," a mainly anti-nuclear power movement, and/or grüne Listen "green lists" (of environmental candidates). Green (adj.) in the sense of "environmental" is attested in English from 1971; Greenpeace, the international conservation and environmental protection group, is from 1971.
Greenwich: town on the south bank of the Thames adjoining London, Old English Gronewic (918), Grenewic (964), literally "green harbor" or "green trading place." The Royal Observatory there was founded June 22, 1675, by King Charles II specifically to solve the problem of finding longitude while at sea. In October 1884, 41 delegates from 25 nations met in Washington, D.C., for the International Meridian Conference. They decided to adopt a single world meridian, passing through the principal Transit Instrument at the observatory at Greenwich, as the basis of calculation for all longitude and a worldwide 24-hour clock. The Greenwich motion passed 22-1; San Domingo voted against it; France and Brazil abstained. The Greenwich Village quarter of New York City has been symbolic of "American bohemia" at least since 1903.
greet (v.): Old English gretan "to come in contact with" in any sense ("attack, accost" as well as "salute, welcome," and "touch, take hold of, handle," as in hearpan gretan "to play the harp"), "seek out, approach," from West Germanic *grotjan (source also of Old Saxon grotian, Old Frisian greta, Dutch groeten, Old High German gruozen, German grüßen "to salute, greet"), of uncertain origin.

In English, German, and Dutch, the primary sense has become "to salute," but the word once had much broader meaning. Perhaps originally "to resound" (via notion of "cause to speak"), causative of Proto-Germanic *grætanan, root of Old English grætan (Anglian gretan) "weep, bewail," from PIE *gher- (2) "to call out." Greet still can mean "cry, weep" in Scottish & northern England dialect, though this might be from a different root. Grætan probably also is the source of the second element in regret. Related: Greeted; greeting.
greeter (n.): late 14c., agent noun from greet.
greeting (n.): Old English greting "salutation," verbal noun from gretan (see greet). Related: Greetings. First record of greeting card is from 1876.
gregarious (adj.): 1660s, "disposed to live in flocks" (of animals), from Latin gregarius "pertaining to a flock; of the herd, of the common sort, common," from grex (genitive gregis) "flock, herd," from PIE *gre-g-, reduplicated form of root *ger- (1) "to gather together, assemble" (source also of Sanskrit gramah "heap, troop;" Greek ageirein "to assemble," agora "assembly;" Latin gremium "bosom, lap;" Old Church Slavonic grusti "handful," gramota "heap;" Lithuanian gurgulys "chaos, confusion," gurguole "crowd, mass"). Of persons, "sociable" first recorded 1789. Related: Gregariously; gregariousness.
Gregorian (adj.): "pertaining to Gregory," from Late Latin Gregorianus, from Gregorius (see Gregory). From c. 1600 of church music, in reference to Gregory I the Great (pope from 590-604), who traditionally codified it; 1640s in reference to new calendar (introduced 1582) from Pope Gregory XIII (1572-1585); due to Protestant resistance, the calendar was not introduced in England and the American colonies until 1752.
Gregory: masc. proper name, popular in England and Scotland by mid-12c. (Pope Gregory I sent the men who converted the English to Christianity), nativization of Late Latin Gregorius, literally "wakeful" (equivalent to Latin Vigilantius), from Greek gregorios, a derivative of gregoros "to be watchful," from PIE root *ger- "to be awake" (source also of Sanskrit jagarti "he is awake," Avestan agarayeiti "wakes up, rouses"). At times confused with Latin gregarius (see gregarious).
gremlin (n.): "small imaginary creature blamed for mechanical failures," oral use in R.A.F. aviators' slang from Malta, the Middle East and India is said to date to 1923. First printed use perhaps in poem in journal "Aeroplane" April 10, 1929; certainly in use by 1941, and popularized in World War II and picked up by Americans (for example "New York Times" Magazine April 11, 1943). Of unknown origin. OED says "probably formed by analogy with GOBLIN." Speculations in Barnhart are a possible dialectal survival of Old English gremman "to anger, vex" + the -lin of goblin; or Irish gruaimin "bad-tempered little fellow." Surfer slang for "young surfer, beach trouble-maker" is from 1961 (short form gremmie by 1962).
Grenada: West Indies island, discovered by Columbus Aug, 15, 1498, and named by him Concepción, the place later was renamed for the old Spanish kingdom or city of Granada. Related: Grenadian.
grenade (n.): "small explosive shell," thrown rather than discharged from a cannon, 1590s, earlier "pomegranate" (1520s), from Middle French grenade "pomegranate" (16c.), earlier grenate (12c.), from Old French pomegrenate (see pomegranate). Form influenced by Spanish granada. So called because the many-seeded fruit suggested the powder-filled, fragmenting bomb, or from similarities of shape. See pomegranate. Much used late 17c., they went out of use 18c. but were revived 20c.
grenadier (n.): 1670s, originally a word for soldiers "who were dexterous in flinging hand-granados" [Evelyn], from French grenadier (15c.), from Middle French grenade "grenade" (see grenade); later "the tallest and finest men in the regiment" [OED]. Grenades went out of use in 18c., but the name was retained by certain companies of regiments.
grenadine (n.): "syrup made from pomegranates," 1896, from French sirop de grenadin from Middle French grenade "pomegranate" (see pomegranate). The type of thin silk fabric, so called from 1851, probably is from Grenada.
Grenoble: city in southeastern France, from Roman Gratianopolis, named for 4c. roman emperor Flavius Gratianus. During the French Revolution the city was briefly renamed Grelibre, as if from noble.
Grepo (n.): East Berlin border guard during the Cold War, by 1964, from German, contraction of Grenzpolizei "border police."
Greta: fem. proper name; see Gretchen.
Gretchen: fem. proper name, German diminutive of Greta, a German and Swedish pet form of Margaret. Somestimes used as a typical German female name, also sometimes in reference to the name of the simple girl seduced by Faust.
Gretna Green: town in Scotland just across the border, proverbial from late 18c. as the customery place for English couples to run off and be married without parental consent.
grew: past tense of grow (v.), from Old English greow, past tense of growan.
grey: see gray.
greyhound (n.): Old English grighund (West Saxon), greghund (Anglian) "greyhound," probably from grig- "bitch," a word of unknown etymology, + hund "dog" (see hound (n.)). The first element in the name apparently has nothing to do with color, as most of the hounds are not gray, but the exact sense of it must have been early forgotten, as it has been long associated with the color in popular imagination. In some Middle English forms it appears to be conformed to Grew, an old word for "Greek" (from Old French Griu). The Old Norse form of the word is preserved in Hjalti's couplet that almost sparked war between pagans and Christians in early Iceland:
Vilkat goð geyja
grey þykkjumk Freyja

(I will not blaspheme the gods,
but I think Freyja is a bitch)
grid (n.): 1839, shortening of gridiron or griddle. City planning sense is from 1954 (hence gridlock). Meaning "network of transmission lines" first recorded 1926.
griddle (n.): shallow frying pan, early 13c., apparently from Anglo-French gridil, Old North French gredil, altered from Old French graille "grill, grating," from Latin craticula "small griddle" (see grill (n.)). Griddle-cake is from 1783.
gridiron (n.): cooking utensil for broiling over a fire, early 14c., griderne, alteration (by association with iron) of gridire (late 13c.), a variant of gridil (see griddle). Confusion of "l" and "r" was common in Norman dialect. Also a medieval instrument of torture by fire. As the word for a U.S. football field, by 1896, for its lines.
gridlock: 1980 (n.); 1987 (v.); from grid (n.) + lock (n.1). Related: Gridlocked; gridlocking.
grief (n.): early 13c., "hardship, suffering, pain, bodily affliction," from Old French grief "wrong, grievance, injustice, misfortune, calamity" (13c.), from grever "afflict, burden, oppress," from Latin gravare "make heavy; cause grief," from gravis "weighty" (see grave (adj.)). Meaning "mental pain, sorrow" is from c. 1300. Good grief as an exclamation of surprise, dismay, etc., is from 1912.
grievance (n.): c. 1300, "state of being aggrieved," from Old French grevance "harm, injury, misfortune; trouble, suffering, agony, sorrow," from grever "to harm, to burden, be harmful to" (see grief). In reference to a cause of such a condition, from late 15c.
grieve (v.): c. 1200, transitive, "to make worried or depressed; to make angry, enrage;" also "to be physically painful, cause discomfort;" c. 1300 as "cause grief to, disappoint, be a cause of sorrow;" also "injure, harass, oppress," from tonic stem of Old French grever "to burden, oppress, aggravate" (see grief). Intransitive sense of "be sorry, lament" is from c. 1400. Related: Grieved; grieving.
griever (n.): "one who causes grief" (obsolete), 1590s, agent noun from grieve. Main modern sense, "one who feels grief," is from 1819.