rosebud (n.) Look up rosebud at Dictionary.com
1610s, from rose (n.1) + bud (n.). Hence, "young girl in her first bloom, a debutante."
rosemary (n.) Look up rosemary at Dictionary.com
late 14c., earlier rosmarine (c.1300), from Latin rosmarinus, literally "dew of the sea" (compare French romarin), from ros "dew" + marinus (see marine (adj.)). Perhaps so called because it grew near coasts. Form altered in English by influence of rose and Mary.

Latin ros is from PIE *ers- "to be wet" (cognates: Lithuanian rasa, Old Church Slavonic rosa "dew," Sanskrit rasah "sap, juice, fluid, essence," Hittite arszi "flows," and perhaps also Rha, Scythian name of the River Volga (see rhubarb)).
Rosetta Stone (n.) Look up Rosetta Stone at Dictionary.com
discovered 1798 at Rosetta, Egypt; now in British Museum. Dating to 2c. B.C.E., its trilingual inscription helped Jean-François Champollion decipher Egyptian demotic and hieroglyphics in 1822, which opened the way to study of all early Egyptian records. Hence, figurative use of the term to mean "something which provides the key to previously unattainable understanding" (1902). The place name is the European form of Rashid, a name given because it was founded c.800 C.E. by Caliph Harun ar-Rashid.
rosette (n.) Look up rosette at Dictionary.com
"a rose-shaped ornament," especially a bunch or knot of ribbons worn as a decoration, 1790, from French rosette, diminutive of rose "rose" (see rose (n.1)).
rosewood (n.) Look up rosewood at Dictionary.com
1650s, from rose (n.1) + wood (n.). The name is due to the scent of some species when freshly cut.
Rosh Hashanah (n.) Look up Rosh Hashanah at Dictionary.com
Jewish new year, 1846, from Hebrew rosh hashshanah, literally "head of the year," from rosh "head of" + hash-shanah "the year."
Rosicrucian (n.) Look up Rosicrucian at Dictionary.com
1620s, from Modern Latin rosa crucis (DuCange) or crux, Latinization of German Rosenkreuz, French rosecroix, from the secret society's reputed founder Christian Rosenkreuz, said to date from 1484, but not mentioned before 1614. As an adjective from 1660s.
rosin (n.) Look up rosin at Dictionary.com
late 13c., from Old French raisine, rousine, variants of résine (see resin). The verb is from mid- 14c. Related: Rosined; rosining.
Rosinante (n.) Look up Rosinante at Dictionary.com
Don Quixote's horse, from Spanish Rocinante, from rocin "worn-out horse" + antes "before," "so called in allusion to the circumstance that Don Quixote's charger was formerly a wretched hack" [Klein]. Rocin is cognate with Old French rancin "draft horse, hack," but the word is of unknown origin.
roster (n.) Look up roster at Dictionary.com
1727, from Dutch rooster "table, list," originally "gridiron," from Middle Dutch roosten "to roast" (see roast (v.)). So called from the grid of lines drawn on a paper to make a list.
rostral (adj.) Look up rostral at Dictionary.com
c.1400, from Late Latin rostralis, from Latin rostrum "beak" (see rostrum).
rostrum (n.) Look up rostrum at Dictionary.com
1540s, from Latin rostrum, name of the platform stand for public speakers in the Forum in ancient Rome. It was decorated with the beaks of ships taken in the first naval victory of the Roman republic, over Antium, in 338 B.C.E., and the word's older sense is "end of a ship's prow," literally "beak, muzzle, snout," originally "means of gnawing," instrument noun form of rodere "to gnaw" (see rodent). Compare claustrum "lock, bar," from claudere "to shut." Extended sense of any platform for public speaking is first recorded 1766. Classical plural form is rostra.
rosy (adj.) Look up rosy at Dictionary.com
late 14c., of a color, from rose (n.1) + -y (2), probably modeled on Old French rose. From 1590s of healthy complexions; 1775 in the sense "cheerful;" meaning "promising" is from 1887. Similar formation in Middle Dutch rosich, Dutch rozig, German rosig.
rot (v.) Look up rot at Dictionary.com
Old English rotian "to decay, putrefy," from Proto-Germanic *rutjan (cognates: Old Saxon roton, Old Norse rotna, Old Frisian rotia, Middle Dutch roten, Dutch rotten, Old High German rozzen "to rot," German rößen "to steep flax"), from stem *rut-. Related: Rotted; rotting.
rot (n.) Look up rot at Dictionary.com
early 14c., from rot (v.) or of Scandinavian origin (compare Icelandic rot, Swedish röta, Danish røde "decay, putrefaction"), from the root of the verb. Slang noun sense of "rubbish, trash" is from 1848.
rotary (adj.) Look up rotary at Dictionary.com
1731, from Medieval Latin rotarius "pertaining to wheels," from Latin rota "a wheel, a potter's wheel; wheel for torture," from PIE root *ret- "to run, to turn, to roll" (cognates: Sanskrit rathah "car, chariot;" Avestan ratho; Lithuanian ratas "wheel," ritu "I roll;" Old High German rad, German Rad, Dutch rad, Old Frisian reth, Old Saxon rath, Old Irish roth, Welsh rhod "carriage wheel"). The international service club (founded by Paul P. Harris in Chicago in 1905) so called from the practice of clubs entertaining in rotation. Hence Rotarian (1911).
rotate (v.) Look up rotate at Dictionary.com
1794, intransitive, back-formation from rotation. Transitive sense from 1823. Related: Rotated; rotating. Rotator "muscle which allows a part to be moved circularly" is recorded from 1670s.
rotation (n.) Look up rotation at Dictionary.com
1550s, from Latin rotationem (nominative rotatio) "a turning about in a circle," noun of action from past participle stem of rotare "turn round, revolve, whirl about, roll," from PIE *ret- "to run, roll" (see rotary).
rotational (adj.) Look up rotational at Dictionary.com
1852, from rotation + -al (1).
rotavirus (n.) Look up rotavirus at Dictionary.com
wheel-shaped virus causing inflammation of the lining of the intestines, 1974, from Latin rota "wheel" (see rotary) + virus.
rote (n.) Look up rote at Dictionary.com
c.1300, "custom, habit," in phrase bi rote "by heart," of uncertain origin, sometimes said to be connected with Old French rote "route" (see route (n.)), or from Latin rota "wheel" (see rotary), but OED calls both suggestions groundless.
rotgut (n.) Look up rotgut at Dictionary.com
also rot-gut, "unwholesome liquor," 1630s, from rot (v.) + gut (n.).
Rothschild Look up Rothschild at Dictionary.com
"rich person," 1833, in reference to the international banking family descended from Mayer Amschel Rothschild (1744-1812) of Frankfurt. The surname is literally "red shield," a house name.
Rotifera (n.) Look up Rotifera at Dictionary.com
class of microscopic freshwater organisms, 1830, Modern Latin, from Rotifer (Leeuwenhoek, 1702), from Latin rota "wheel" (see rotary) + -fer "bearing" (see bear (v.)). The animalcules use rotary organs to swim about.
rotisserie (n.) Look up rotisserie at Dictionary.com
1868, "restaurant where meat is roasted on a spit," from French rôtisserie "shop selling cooked food, restaurant," from present participle stem of rôtir "to roast," from Old French rostir (see roast (v.)). As an in-home cooking apparatus, attested from 1953. Manufacturers (or their copy writers) back-formed a verb, rotiss (1958). Rotisserie league (1980), a form of fantasy baseball, is based on La Rotisserie, the Manhattan restaurant where it was conceived.
rotogravure (n.) Look up rotogravure at Dictionary.com
1913, from German Rotogravur (originally, in full, Deutsche Tiefdrück Gesellschaft), said to blend two corporate names, Rotophot and Deutsche Photogravur A.G. Etymologically, the roots are Latin rota "wheel, roller" (see rotary) and French gravure "engraving" (see gravure). The process was used for printing photo sections of newspapers and magazines, so that the word came to be used for these.
rotor (n.) Look up rotor at Dictionary.com
1873, irregular shortening of rotator (see rotate (v.)), originally in mathematics. Mechanical sense is attested from 1903; specifically of helicopters from 1930.
Rototiller (n.) Look up Rototiller at Dictionary.com
1923, from roto-, from Latin rota "wheel" (see rotary) + tiller.
rotten (adj.) Look up rotten at Dictionary.com
c.1300, from a Scandinavian source akin to Old Norse rotinn "decayed," past participle of verb related to rotna "to decay," from Proto-Germanic stem *rut- (see rot (v.)). Sense of "corrupt" is from late 14c.; weakened sense of "bad" first recorded 1881. Rotten apple is from a saying traced back to at least 1528: "For one rotten apple lytell and lytell putrifieth an whole heape." The Rotten Row in London and elsewhere probably is from a different word, but of uncertain origin.
rottenness (n.) Look up rottenness at Dictionary.com
late 14c., from rotten + -ness.
rotter (n.) Look up rotter at Dictionary.com
"person deemed objectionable on moral grounds," 1889, slang, from rot + -er (3).
Rottweiler (n.) Look up Rottweiler at Dictionary.com
1907, from Rottweil, town in Württemberg, southern Germany.
rotund (adj.) Look up rotund at Dictionary.com
1705, from Latin rotundus "rolling, round, circular, spherical, like a wheel," from rota "wheel" (see rotary). Earlier was rotound (1610s); rotounde (early 15c.). Meaning "full-toned style of oratory" (1830) is after Horace's ore rotundo in "Poetics."
rotunda (n.) Look up rotunda at Dictionary.com
"round building," 1680s, from Italian rotonda, especially the Pantheon, from noun use of Latin rotunda, fem. of rotundus "round" (see rotund). Meaning "circular hall or room within a building" is from 1780.
rotundity (n.) Look up rotundity at Dictionary.com
1580s, from Latin rotunditas "roundness," from rotundus "round" (see rotund).
Rotwelsch (n.) Look up Rotwelsch at Dictionary.com
"jargon of thieves and vagabonds," 1841, from German Rotwelsch, literally "Red Welsh," from rot (see red (adj.1)) + Welsh because obscure and difficult. But the first element may be connected with Middle High German rot "beggar."
roue (n.) Look up roue at Dictionary.com
"debauchee," 1800, from French roué "dissipated man, rake," originally past participle of Old French rouer "to break on the wheel" (15c.), from Latin rotare "roll" (see rotary). Said to have been first applied in French c.1720 to dissolute friends of the Duke of Orleans (regent of France 1715-23), to suggest the punishment they deserved; but probably rather from a secondary, figurative sense in French of "jaded, worn out," from the notion of "broken, run-over, beat down."
Rouen Look up Rouen at Dictionary.com
city in northern France, Roman Rotomagus, in which the second element is Gaulish magos "field, market," and the first is roto "wheel," perhaps reflecting the Gaulish love of chariot-racing, or else it is a personal name.
rouge (n.) Look up rouge at Dictionary.com
1753, in cosmetic sense, "blush," from French rouge "red coloring matter," noun use of adjective "red" (12c.), from Latin rubeus, related to ruber "red" (see red). Replaced native paint in this sense. The verb is attested from 1777. Related: Rouged; rouging. The same word had been borrowed from French in Middle English with the sense "red color; red" (early 15c.).
rough (n.) Look up rough at Dictionary.com
c.1200, "broken ground," from rough (adj.). Meaning "a rowdy" is first attested 1837. Specific sense in golf is from 1901. Phrase in the rough "in an unfinished or unprocessed condition" (of timber, etc.) is from 1819.
rough (adj.) Look up rough at Dictionary.com
Old English ruh "rough, coarse (of cloth); hairy, shaggy; untrimmed, uncultivated," from West Germanic *rukhwaz "shaggy, hairy, rough" (cognates: Middle Dutch ruuch, Dutch ruig, Old High German ruher, German rauh), from Proto-Germanic *rukhaz, from PIE *reue- (2) "to smash, knock down, tear out, dig up" (cognates: Sanskrit ruksah "rough;" Latin ruga "wrinkle," ruere "to rush, fall violently, collapse," ruina "a collapse;" Lithuanian raukas "wrinkle," rukti "to shrink").

The original -gh- sound was guttural, as in Scottish loch. Sense of "approximate" is first recorded c.1600. Of places, "riotous, disorderly, characterized by violent action," 1863. Rough draft is from 1690s. Rough-and-ready is from 1810, originally military; rough-and-tumble (1810) is from a style of free-fighting.
rough (v.) Look up rough at Dictionary.com
late 15c., from rough (adj.). Related: Roughed; roughing. Phrase rough it "submit to hardships" (1768) is originally nautical:
To lie rough; to lie all night in one's clothes: called also roughing it. Likewise to sleep on the bare deck of a ship, when the person is commonly advised to chuse the softest plank. [Grose, "Dictionary of the Vulgar Tongue," 1788]
To rough out "shape or plan approximately" is from 1770. To rough up "make rough" is from 1763. To rough (someone) up "beat up, jostle violently" is from 1868. The U.S. football penalty roughing was originally a term from boxing (1866).
rough rider (n.) Look up rough rider at Dictionary.com
1733, "horse-breaker," from rough (adj. or adv.) + rider. In specific military use, a non-commissioned officer in cavalry regiments, from 1802; meaning "irregular cavalryman" is attested from 1884.
rough-hewn (adj.) Look up rough-hewn at Dictionary.com
1520s, originally of timber, from rough-hew (v.); see rough (adj.) + hew (v.).
rough-house (n.) Look up rough-house at Dictionary.com
1887, "uproar, disturbance," from rough (adj.) + house (n.). The verb is first attested 1896. Related: Rough-housing.
roughage (n.) Look up roughage at Dictionary.com
1883, "rough grass or weeds," from rough (adj.) + -age. Meaning "coarse, bulky food" first recorded 1927.
roughen (v.) Look up roughen at Dictionary.com
1580s, from rough (adj.) + -en (1). Related: Roughened; roughening.
roughly (adv.) Look up roughly at Dictionary.com
c.1300, "ungently, violently," from rough (adj.) + -ly (2). Meaning "approximately, without precision or exactness" is from 1841.
roughneck (n.) Look up roughneck at Dictionary.com
also rough-neck, 1836, "rugged individual," from rough (adj.) + neck (n.). Original context is the Texas frontier, later adpoted to labor organization toughs. Specific sense of "oil rig worker" is recorded from 1917. Compare redneck.
roughness (n.) Look up roughness at Dictionary.com
late 14c., from rough (adj.) + -ness.