Online Etymology Dictionary

rive (v.): "tear in pieces, strike asunder," late 13c., from Old Norse rifa "to tear apart" (see riparian).
riven (adj.): "split, cloven, rent," c.1300, past participle adjective from rive "to tear, rend."
river (n.): c.1300, from Old French riviere, from Vulgar Latin *riparia "riverbank, seashore, river" (cf. Spanish ribera, Italian riviera), noun use of fem. of Latin riparius "of a riverbank" (see riparian). The Old English word was ea "river," cognate with Gothic ahwa, Latin aqua (see aqua-).

U.S. slang phrase up the river "in prison" (1891) is originally in reference to Sing Sing prison, which was literally "up the (Hudson) river" from New York City. Phrase down the river "done with" perhaps echoes sense in to sell down the river (1851), originally of troublesome slaves, to sell from the Upper South to the harsher cotton plantations of the Deep South.
riverine (adj.): 1860, from river + -ine (1).
rivet (n.): c.1400, from Old French rivet, possibly from Middle Dutch wriven "turn, grind." The English word may be directly from Middle Dutch.
rivet (v.): early 15c., from rivet (n.). Meaning "to command the attention" is from c.1600. Related: Riveted; riveting.
riveting (adj.): "commanding attention," 1854, present participle adjective from rivet (v.).
Riviera: "Mediterranean seacoast around Genoa," 1630s, from Italian riviera, literally "bank, shore" (see river). In extended use, the coast from Marseilles to La Spezia, which became popular 19c. as a winter resort.
rivulet (n.): 1580s, from Italian rivoletto, diminutive of rivolo, itself a diminutive, from Latin rivus "stream, brook," from PIE *reiwos, literally "that which flows," from root *reie- "to flow, run" (see Rhine).
RNA (n.): 1948, abbreviation of ribonucleic acid (see ribonucleic).
roach (n.1): 1837, shortened form of cockroach, in contemporary writing said to be from a polite desire to avoid the sexual connotation in the first syllable; meaning "butt of a marijuana cigarette" is first recorded 1938, perhaps from resemblance to the insect, but perhaps a different word entirely.
roach (n.2): small freshwater fish, early 14c., from Old French roche (13c.), perhaps from a Germanic source.
road (n.): Old English rad "riding, hostile incursion," from Proto-Germanic *ridanan, source of Old English ridan (see ride). Also related to raid. In Middle English, "a riding, a journey;" sense of "open way for traveling between two places" is first recorded 1590s. Modern spelling established 18c.

Road test is from 1906. Road hog is attested from 1886; road rage is from 1988. Road map is from 1786; road trip is by 1950, originally of baseball teams.
road kill (n.): animal killed by vehicular traffic, 1972; the figurative sense is from 1992.
roadblock (n.): 1940, from road + block (n.).
roadie (n.): "laborer employed by pop groups while on tour," 1969, from road + -ie.
roadster (n.): "open two-seat automobile," 1908; earlier of light carriages (1892), originally "a ship lying near the shore" (1744), from road (n.) in nautical sense of "narrow stretch of sheltered water" (early 14c., e.g. Hampton Roads in Virginia) + -ster.
roam (v.): c.1300, romen, possibly from Old English *ramian "act of wandering about," related to aræman "arise, lift up." There are no cognate forms in other Germanic languages. "Except in late puns, there is no evidence of connexion with the Romance words denoting pilgrims or pilgrimages to Rome ...." [OED]. Related: Roamed; roaming.
roan (adj.): 1520s, from Middle French roan "reddish brown," perhaps from Spanish roano, from Old Spanish raudano, probably from a Germanic source (cf. Gothic raudan, accusative of rauðs "red").
roar (v.): Old English rarian, probably of imitative origin (cf. Middle Dutch reeren, German röhren "to roar;" Sanskrit ragati "barks;" Lithuanian reju "to scold;" Old Church Slavonic revo "I roar;" Latin raucus "hoarse"). Related: Roared; roaring. Roaring forties in reference to exceptional rough seas between latitudes 40 and 50 south, is attested from 1841.
roar (n.): late 14c., from roar (v.).
roast (v.): c.1300, from Old French rostir, from Frankish *hraustjan (cf. Old High German rosten, Middle Dutch roosten "to roast"), from the same source as roster. The meaning "make fun of in an affectionate way" is from 1710. Related: Roasted; roasting. Roast beef first recorded 1630s.
roast (n.): early 14c.; see roast (v.).
rob (v.): late 12c., from Old French rober, from a Germanic source (cf. Old High German roubon "to rob," roub "spoil, plunder;" Old English reafian, source of the reave in bereave; see reave), from Proto-Germanic *raubojanan, from *raub- "to break."
Lord, hou schulde God approve þat þou robbe Petur, and gif þis robbere to Poule in þe name of Crist? [Wyclif, c.1380]
To rob the cradle is attested from 1864 in relation to drafting young men in the American Civil War; by 1949 in romantic sense. Related: Robbed; robbing.
Rob Roy: Highland freebooter (1671-1734). His name means "Red Robert." As a type of cocktail made with Scotch whiskey, it is attested from 1960.
robber (n.): late 12c., from Old French robbere, agent noun from rober (see rob). Robber baron in the "corrupt, greedy financier" sense is attested from 1870s, from a comparison of Gilded Age capitalists to medieval European warlords.
It is the attempt of the more shrewd to take advantage of the less shrewd. It is the attempt of the strong to oppress the weak. It is tho old robber baron in his castle descending, after men have planted their crops, and stealing them. [Henry Ward Beecher, sermon, "Truthfulness," 1871]

Regulation by combination means that the railroad managers are feudal lords and that you are their serfs. It means that every car load of grain or other produce of your fields and shops that passes over the New York Central shall pay heavy toll for right of transit to Vanderbilt, the robber baron of our modern feudalism, who dominates that way. [W.C. Flagg, testimony to Congress, 1874]
robbery (n.): c.1200, from Old French roberie, from rober (see rob).
robe (n.): late 13c., from Old French robe "long, loose outer garment," originally "plunder, booty," from a Germanic source (cf. Old High German rouba "vestments," presumably those taken from the enemy as spoils), from West Germanic *rauba, the stem that also yielded rob (v.). Metonymic sense of "the legal profession" is attested from 1640s.
robe (v.): late 14c., from robe (n.). Related: Robed; robing.
Robert: masc. proper name, from Old North French form of Old High German Hrodberht, literally "bright with glory," from hrod- "fame, glory" + -berht "bright."
robin (n.): common European songbird, 1540s, shortening of Robin Redbreast (mid-15c.), from masc. personal name Robin. It ousted the native ruddock, which is related to red. In North America, the name was applied to the red-breasted thrush by 1703. Robin's egg as a shade of blue is attested from 1881.
Robin: masc. proper name, from Old French Robin, diminutive of Robert (q.v.). Robin Goodfellow "sportive elf of the English countryside," is first attested 1530s, popular 16-17c.; Robin Hood is at least from late 14c.
Robinson Crusoe: "man without companionship," 1768, from name of the eponymous hero of Daniel Defoe's fictional shipwreck narrative (1719).
robot (n.): 1923, from English translation of 1920 play "R.U.R." ("Rossum's Universal Robots"), by Karel Capek (1890-1938), from Czech robotnik "slave," from robota "forced labor, drudgery," from robotiti "to work, drudge," from an Old Czech source akin to Old Church Slavonic rabota "servitude," from rabu "slave" (see orphan), from a Slavic stem related to German Arbeit "work" (Old High German arabeit). According to Rawson the word was popularized by Karel Capek's play, "but was coined by his brother Josef (the two often collaborated), who used it initially in a short story."
robotics (n.): 1941, from robot + -ics. Coined in a science fiction context by Russian-born U.S. author Isaac Asimov (1920-1992), who proposed the "Three Laws of Robotics" in 1968.
robust (adj.): 1540s, from Latin robustus "strong and hardy," originally "oaken," from robur, robus "hard timber, strength," also "a special kind of oak," named for its reddish heartwood, from Latin ruber "red" (cf. robigo "rust"). Robustious (1540s) was a common form in 17c. (cf. "Hamlet" iii.2); it fell from use by mid-18c., but was somewhat revived by mid-19c. antiquarian writers.
roc (n.): large, ferocious bird of fable, 1570s, from Arabic rukhkh, from Persian rukh. Mentioned in Marco Polo's account of Madagascar, modern use is mostly from "Arabian Nights."
rock (n.): "stone," Old English rocc (in stanrocc "stone rock or obelisk"), also from Old North French roque, from Medieval Latin rocca (767), from Vulgar Latin *rocca, of uncertain origin, sometimes said to be from Celtic (cf. Breton roch).

It seems to have been used in Middle English principally for rock formations as opposed to individual stones. Meaning "precious stone, especially a diamond," is 1908, U.S. slang. Figurative use for "sure foundation" (especially with reference to Christ) is from 1520s. Meaning "crystalized cocaine" is attested from 1973, in West Coast U.S. slang. Rock-bottom "lowest possible" is from 1856. Rock-salt is from 1707. Rock-ribbed is from 1776, originally of land; figurative sense of "resolute" first recorded 1887. Between a rock and a hard place first attested 1921:
to be between a rock and a hard place, vb. ph. To be bankrupt. Common in Arizona in recent panics; sporadic in California. ["Dialect Notes," vol. V, part iv, 1921]
rock (v.1): "to sway," late Old English roccian, related to Old Norse rykkja "to pull, tear, move," Swedish rycka "to pull, pluck," Middle Dutch rucken, Old High German rucchan, German rücken "to move jerkily." For musical senses, see rock (v.2). Rocking horse is first recorded 1724; rocking chair is from 1766. To rock the boat in the figurative sense "stir up trouble" is from 1914. Rock-a-bye first recorded 1805 in nursery rhyme.
rock (v.2): "to dance to popular music with a strong beat," 1948 (first attested in song title "We're gonna rock"), from rock (v.1), in earlier blues slang sense of "to cause to move with musical rhythm" (1922); often used at first with sexual overtones (cf. 1922 song title "My Man Rocks Me (with One Steady Roll)"). Sense developed early 1950s to "play or dance to rock and roll music." Noun sense of "musical rhythm characterized by a strong beat" is from 1946, in blues slang. Rock star attested by 1966. Rocksteady, Jamaican pop music style (precursor of reggae), is attested from 1969.
rock and roll (n.): also rock 'n' roll, 1954 in reference to a specific style of popular music, from rock (v.2) + roll (v.). The verbal phrase had been a Black English euphemism for "sexual intercourse," used in popular dance music lyrics and song titles since at least the 1934s. Shortened form rock first attested 1957.
rockabilly (n.): 1956, from noun sense of rock (v.2), with the second element abstracted from (hill)billy music. First attested in a "Billboard" item about Johnny Burnette's "Lonesome Train."
Rockefeller (n.): "immensely rich man," 1938, in reference to U.S. financier and philanthropist John D. Rockefeller (1839-1937).
rocker (n.): "a rocking chair," 1852, American English, from rock (v.); earlier "nurse charged with rocking a cradle" (c.1400). In sense of "one of the curved pieces of wood that makes a chair or cradle rock" it dates from 1787. Slang off (one's) rocker "crazy" first recorded 1897. Meaning "one who enjoys rock music" (as opposed to mod) is recorded from 1963.
rocket (n.1): "garden plant of the cabbage family," 1520s, from Middle French roquette, from Italian rochetta, diminutive of ruca "a kind of cabbage," from Latin eruca "colewort," perhaps literally "hairy caterpillar" (the plant has downy stems) and related to ericus "hedgehog," also "a beam set with spikes."
rocket (n.2): "projectile," 1610s, from Italian rocchetto "a rocket," literally "a bobbin," diminutive of rocca "a distaff," so called because of cylindrical shape. The Italian word probably is from a Germanic source (cf. Old High German rocko "distaff," Old Norse rokkr), from Proto-Germanic *rukka-, from PIE root *rug- "to spin."

Originally "fireworks rocket," meaning "device propelled by a rocket engine" first recorded 1919; rocket-ship in the modern sense first attested 1927 ("Popular Science"); earlier as a type of naval warship firing projectiles. Rocket science in the figurative sense of “difficult, complex process or topic” is attested by 1985. Rocket scientist is from 1952.
rocket (v.): "to spring like a rocket," 1860, from rocket (n.2). Earlier "to attack with rockets" (1799). Related: Rocketed; rocketing.
rocketry (n.): 1930, from rocket (n.2) + -ry.
rocks (n.): plural of rock (n.). Meaning "ice cubes" is from 1946; slang meaning "testicles" is first recorded in phrase get (one's) rocks off "achieve intense satisfaction." On the rocks "ruined" is from 1889.
rocky (adj.): "full of rocks," c.1400, from rock (n.) + -y (2); "unsteady," 1737, from rock (v.1). Meaning "difficult, hard" is recorded from 1873, and may represent a bit of both.