Origin and history of ray

ray(n.1)

"beam of light, light emitted in a given direction from a luminous body," early 14c., rai, from Old French rai (nominative rais) "ray (of the sun), spoke (of a wheel); gush, spurt," from Latin radius "ray, spoke, staff, rod" (see radius). Not common before 17c. [OED]; of the sun, usually in reference to heat (beam being preferred for light).

Ray is usually distinguished from beam, as indicating a smaller amount of light; in scientific use a beam is a collection of parallel rays. In ordinary language ray is the word usually employed when the reference is to the heat rather than the light of the sun .... [OED]

Science fiction's ray-gun is recorded by 1931 (in Amazing Stories; electric ray gun as an imaginary weapon is from 1924; death-ray gun from 1926 as a prop in a vaudeville act), but the Martians had a Heat-Ray weapon in "War of the Worlds" (1898).

also from early 14c.

ray(n.2)

"a skate, type of fish related to sharks and noted for its broad, flat body," early 14c., raie, from Old French raie (13c.) and directly from Latin raia. De Vaan describes this as a word of unknown origin but with apparent cognates in Germanic (Middle Dutch rogghe, Old English reohhe), perhaps a loan-word from a substrate language. The old etymology (Century Dictionary, etc.) was that the fish was so called from its resemblance to the rays of a fan and from the source of ray (n.1).

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]

also from early 14c.

Entries linking to ray

radius(n.)

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).

rayon(n.)

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.

sting-ray(n.)

also stingray, type of batoid fish with a long lash-like tail with a bony spine near its base that inflicts a painful wound, 1620s, from sting + ray (n.2). First in Capt. John Smith's writings: "Stingraies, whose tailes are very dangerous ...." Stingaree (1838) is a variant attested in Australia and U.S.