rockabilly (n.)youdaoicibaDictYouDict[rockabilly 词源字典]
1956, from noun sense of rock (n.2) in the music sense + second element abstracted from hillbilly music. One of the first uses is in a "Billboard" item about Johnny Burnette's "Lonesome Train."[rockabilly etymology, rockabilly origin, 英语词源]
Rockefeller (n.)youdaoicibaDictYouDict
"immensely rich man," 1938, in reference to U.S. financier and philanthropist John D. Rockefeller (1839-1937).
rocker (n.)youdaoicibaDictYouDict
"a rocking chair," 1852, American English, from rock (v.1); earlier "nurse charged with rocking a cradle" (early 14c.). 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 (n.1)) is recorded from 1963, from rock (v.2).
rocket (n.1)youdaoicibaDictYouDict
garden plant of the cabbage family, c. 1500, from Middle French roquette (16c.), from Italian rochetta, diminutive of ruca "a kind of cabbage," from Latin eruca "colewort," perhaps so called for its downy stems and related to ericus "hedgehog," also "a beam set with spikes," from PIE *ghers- "to bristle" (see horror).
rocket (n.2)youdaoicibaDictYouDict
type of self-propelling 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 (compare Old High German rocko "distaff," Old Norse rokkr), from Proto-Germanic *rukkon-, from PIE root *rug- "fabric, spun yarn."

Originally "fireworks rocket," meaning "device propelled by a rocket engine" first recorded 1919; rocket-ship in the modern sense first attested February 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.
That such a feat is considered within the range of possibility is evidenced by the activities of scientists in Europe as well as in America. Two of them, Prof. Herman Oberth and Dr. Franz Hoeff, of Vienna, are constructing a five-ton rocket ship in which they hope to reach the moon in two days. ["Popular Science," Feb. 1927]
rocket (v.)youdaoicibaDictYouDict
"to spring like a rocket," 1860, from rocket (n.2). Earlier "to attack with rockets" (1799). Related: Rocketed; rocketing.
rocketry (n.)youdaoicibaDictYouDict
1930, from rocket (n.2) + -ry.
Rockies (n.)youdaoicibaDictYouDict
"the Rocky Mountains," 1827; see rocky.
rocking (adj.)youdaoicibaDictYouDict
"moving back and forth or to and fro," late 14c., present participle adjective from rock (v.1). Of music, from 1949 (see rock (v.2)). Rocking-horse is first recorded 1724; rocking-chair is from 1766.
rocks (n.)youdaoicibaDictYouDict
plural of rock (n.1). 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, figurative use of the expression with reference to ships (by 1735).
rocky (adj.)youdaoicibaDictYouDict
"full of rocks," c. 1400, from rock (n.1) + -y (2); "unsteady," 1737, from rock (v.1). Meaning "difficult, hard" is recorded from 1873, and may represent a bit of both.

The Rocky Mountains so called by 1802, translating French Montagnes Rocheuses, first applied to the Canadian Rockies. "The name is not directly self-descriptive but is an approximate translation of the name of the former Native American people here known as the Assiniboin .... The mountains are in fact not noticeably rocky" [Room]. Bright notes that "These Indians were called /assiniipwaan/, lit. 'stone Sioux', by their Cree (Algonkian) neighbors".
rococo (adj.)youdaoicibaDictYouDict
1836, "old-fashioned," from French rococo (19c.), apparently a humorous alteration of rocaille "shellwork, pebble-work" from Middle French roche "rock," from Vulgar Latin *rocca "stone." Specifically of furniture or architecture of the time of Louis Quatorze and Louis Quinze, from 1841. If this is correct, the reference is to the excessive use of shell designs in this lavish style. For differentiation, see baroque. The general sense of "tastelessly florid or ornate" is from 1844.
Much of the painting, engraving, porcelain-work, etc., of the time has ... a real decorative charm, though not of a very high order in art. Hence rococo is used attributively in contempt to note anything feebly pretentious and tasteless in art or literature. [Century Dictionary, 1902]
rod (n.)youdaoicibaDictYouDict
Old English rodd "a rod, pole," which is probably cognate with Old Norse rudda "club," from Proto-Germanic *rudd- "stick, club," from PIE *reudh- "to clear land."

As a long, tapering elastic pole for fishing, from mid-15c. Figurative sense of "offshoot" (mid-15c.) led to Biblical meaning "scion, tribe." As an instrument of punishment, attested from mid-12c.; also used figuratively for "any sort of correction or punishment," but the basic notion is of beating someone with a stick.

As a unit of measure (5½ yards or 16½ feet, also called perch or pole) first attested mid-15c., from the stick used to measure it off. As a measure of area, "a square perch," from late 15c., the usual measure in brickwork. Meaning "light-sensitive cell in a retina" is from 1866, so-called for its shape. Slang meaning "penis" is recorded from 1902; that of "gun, revolver" is from 1903.
rodeyoudaoicibaDictYouDict
past tense of ride (q.v.).
rodent (n.)youdaoicibaDictYouDict
1835 (as an adjective 1833), from Modern Latin Rodentia, the order name, from Latin rodentem (nominative rodens), present participle of rodere "to gnaw, eat away," from PIE root *red- "to scrape, scratch, gnaw" (cognates: Sanskrit radati "scrapes, gnaws," radanah "tooth;" Latin radere "to scrape;" Welsh rhathu "scrape, polish"). Uncertain connection to Old English rætt (see rat (n.)).
rodeo (n.)youdaoicibaDictYouDict
1914 as public entertainment show of horse-riding skill, from earlier meaning "cattle round-up" (1834), from Spanish rodeo, "pen for cattle at a fair or market," literally "a going round," from rodear "go round, surround," related to rodare "revolve, roll," from Latin rotare "go around" (see rotary).
RoderickyoudaoicibaDictYouDict
also Roderic, masc. proper name, from Old High German Hroderich, literally "ruling in fame," from hruod- "fame, glory" + Proto-Germanic *rikja "rule" (see rich). Italian and Spanish Rodrigo, Russian Rurik are from German.
rodomontade (n.)youdaoicibaDictYouDict
1610s (earlier rodomontado, 1590s), "vain boasting like that of Rodomonte," character in Ariosto's "Orlando Furioso." In dialectal Italian the name means literally "one who rolls (away) the mountain."
roe (n.1)youdaoicibaDictYouDict
"fish eggs," mid-15c., probably from an unrecorded Old English *hrogn, from Proto-Germanic *khrugna (cognates: Old Norse hrogn, Danish rogn, Swedish rom, Flemish rog, Middle Low German and Middle Dutch roge, Old High German rogo, German Rogen "roe"), from PIE *krek- "frog spawn, fish eggs" (cognates: Lithuanian kurkle, Russian krjak "spawn of frogs"). Exact relations of the Germanic words are uncertain.
roe (n.2)youdaoicibaDictYouDict
"small deer," Old English ra, from raha, from Proto-Germanic *raikhaz (cognates: Old Norse ra, Old Saxon reho, Middle Dutch and Dutch ree, Old High German reh, German Reh "roe"), of uncertain origin; perhaps from PIE root *rei- "streaked, spotted, striped in various colors."