1918, "x-ray dose unit," a shortened form of radiation (q.v.). The meaning "unit of absorbed dose of ionizing radiation" is by 1954, an acronym from radiation absorbed dose. As shortened form of radical (n.), it is attested in political slang from 1820. Teen slang adjectival sense of "extraordinary, wonderful" is from late 1970s (see radical (adj.)).
c. 1400, "of or like a ray or radius," from Medieval Latin radialis, from Latin radius "shaft, rod; spoke of a wheel; beam of light" (see radius). Meaning "arranged like the radii of a circle" is by 1750. As a noun, "a radiating or radial part," by 1872. As a type of tire, attested from 1965, short for radial-ply (tire), so called because the cords run at right angles to the circumference. Related: Radially.
"type of flat, cartilaginous fish, a kind of ray," mid-14c., scate, in reference to the common European skate, from a Scandinavian source such as Old Norse skata "skate," Danish skade, Faeroese skøta, a word of unknown origin.
All skates are rays, but all rays are not called skates, this name being applied chiefly to certain small rays of the restricted genus Raia, of both Europe and America. [Century Dictionary]
1610s, from French tube (15c.), from Latin tubus "tube, pipe," a word of unknown origin. The London subway was christened the Twopenny Tube by 1900 (H.D. Browne, in the "Londoner" of June 30); tube for "cylindrical railway tunnel" is attested from 1847. The meaning "TV as a medium" is from 1959, short for cathode ray tube or picture tube. Tube top as a women's clothing style is attested from 1972. Tube steak is attested from 1963 as "frankfurter," slang meaning "penis" is recorded by mid-1980s.
type of manufactured fiber, 1924, chosen by National Retail Dry Goods Association of America, probably from French rayon "beam of light, ray," from rai (see ray (n.1)) and so called because it is shiny. A marketer's alternative to the original patented name, artificial silk (1884) and the other marketing attempt, Glos, which was "killed by ridicule" [Draper's Record, June 14, 1924].
[T]he production of rayon in American plants, which in 1920 had been only eight million pounds, had by 1925 reached fifty-three million pounds. The flesh-colored stocking became as standard as the short skirt. ... No longer were silk stockings the mark of the rich; as the wife of a workingman with a total family income of $1,638 a year told the authors of Middletown, "No girl can wear cotton stockings to high school. Even in winter my children wear silk stockings with lisle or imitations underneath." [Frederick Lewis Allen, "Only Yesterday," 1931]
By coincidence, Old French rayon had been borrowed into Middle English centuries earlier as a name for a type of cloth.
1590s, "cross-shaft, straight rod or bar," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle," a word of unknown origin. Perhaps related to radix "root," but de Vaan finds that "unlikely." The classical plural is radii.
The geometric sense of "straight line drawn from the center of a circle to the circumference" is recorded from 1650s. Meaning "circular area of defined distance around some place" is attested from 1853. As the name of the shorter of the two bones of the forearm from 1610s in English (the Latin word had been used thus by the Romans).
"allegorical or metaphorical narrative, usually having a moral for instruction," late 13c., parabol, modern form from early 14c., "saying or story in which something is expressed in terms of something else," from Old French parable "parable, parabolic style in writing" (13c.), from Latin parabola "comparison," from Greek parabolē "a comparison, parable," literally "a throwing beside," hence "a juxtaposition," from para- "alongside" (see para- (1)) + bolē "a throwing, casting, beam, ray," related to ballein "to throw" (from PIE root *gwele- "to throw, reach").
Rendered in Old English as bispell. In Vulgar Latin, parabola took on the meaning "word," hence Italian parlare, French parler "to speak" (see parley (n.)).
also pixy, "a fairy," in the rural parts of England associated with the "fairy rings" of old pastures, where they are supposed to dance by moonlight, c. 1630, a word of obscure origin, perhaps from or related to Swedish dialect pyske "small fairy," but the word's original home ("from Cornwall to Wiltshire and Dorset" - OED) suggests it might be Celtic, from Cornwall. The earliest printed references are in pixy-path "bewilderment," literally "path on which one is led astray by pixies," and pixie-led "lost, bewildered." Pixie-puff (1847) was a species of fungus; pixie-purse is an ovicapsule of a shark, skate, or ray found washed up on the shore.
"having popular appeal," 1926, of individual songs from many genres; 1954 as a noun, as genre of its own; abbreviation of popular; earlier as a shortened form of popular concert (1862), and often in the plural form pops. Pop art is recorded from 1957, said to have been in use conversationally among Independent group of artists from late 1954. Pop culture attested from 1958, short for popular culture (which is attested by 1846).
To dismiss him [Johnnie Ray] out of hand one would have to share (as I can't) that facile contempt for "pop" culture, and by implication "pop" audiences, which is the principal flaw of that ambitious new musical, "Expresso Bongo." [Kenneth Tynan, "At the Theatre," The Observer, May 11, 1958]
late 14c., twiteren, in reference to birds, of imitative origin (compare Old High German zwizziron, German zwitschern, Danish kvidre, Old Swedish kvitra). The noun meaning "condition of tremulous excitement" is attested from 1670s. The microblogging service with the 140-character limit was introduced in 2006. The following is considered an unrelated word of obscure origin:
TWITTER. 1. "That part of a thread that is spun too small." Yarn is said to be twined to twitters, when twined too small, S. Hence, to twitter yarn, to spin it unequally, A. Bor. Ray.
2. It is transferred to any person or thing that is slender or feeble. It is said of a lank delicate girl: "She is a mere twitter," S. [Jamieson, "Etymological Dictionary of the Scottish Language," Edinburgh, 1808]