black (adj.)youdaoicibaDictYouDict[black 词源字典]
Old English blæc "dark," from Proto-Germanic *blakaz "burned" (cognates: Old Norse blakkr "dark," Old High German blah "black," Swedish bläck "ink," Dutch blaken "to burn"), from PIE *bhleg- "to burn, gleam, shine, flash" (cognates: Greek phlegein "to burn, scorch," Latin flagrare "to blaze, glow, burn"), from root *bhel- (1) "to shine, flash, burn;" see bleach (v.).

The same root produced Old English blac "bright, shining, glittering, pale;" the connecting notions being, perhaps, "fire" (bright) and "burned" (dark). The usual Old English word for "black" was sweart (see swart). According to OED: "In ME. it is often doubtful whether blac, blak, blake, means 'black, dark,' or 'pale, colourless, wan, livid.' " Used of dark-skinned people in Old English.

Of coffee, first attested 1796. Meaning "fierce, terrible, wicked" is late 14c. The color of sin and sorrow since at least c. 1300; sense of "with dark purposes, malignant" emerged 1580s (as in black magic). Black face in reference to a performance style originated in U.S., is from 1868. Black flag, flown (especially by pirates) as a signal of "no mercy," from 1590s. Black dog "melancholy" attested from 1826. Black belt is from 1875 in reference to districts of the U.S. South with heaviest African population; 1870 with reference to fertility of soil; 1913 in judo sense. Black power is from 1966, associated with Stokely Carmichael.[black etymology, black origin, 英语词源]
G-string (n.)youdaoicibaDictYouDict
1878, geestring, "loincloth worn by an American Indian," originally the string that holds it up, etymology unknown. The spelling with G (1882) is perhaps from influence of violin string tuned to a G (in this sense G string is first recorded 1831), the lowest and heaviest of the violin strings. First used of women's attire 1936, with reference to strip-teasers.
I AM the spirit of the silver "G":
I am silvered sadness,
I am moonlit gladness,
I am that fine madness
Of reverence half, and half of ecstasy
[from "Spirit of the 'G' String," Alfred L. Donaldson, in "Songs of My Violin," 1901]
gun (n.)youdaoicibaDictYouDict
mid-14c., gunne "an engine of war that throws rocks, arrows or other missiles from a tube by the force of explosive powder or other substance," apparently a shortening of woman's name Gunilda, found in Middle English gonnilde "cannon" and in an Anglo-Latin reference to a specific gun from a 1330 munitions inventory of Windsor Castle ("... una magna balista de cornu quae Domina Gunilda ..."). Also compare gonnilde gnoste "spark or flame used to fire a cannon" (early 14c.). The woman's name is from Old Norse Gunnhildr, a compound of gunnr and hildr, both meaning "war, battle." First element from PIE *gwhen- "to strike, kill" (see bane); for second, see Hilda. The identification of women with powerful weapons is common historically (such as Big Bertha, Brown Bess, Mons Meg, etc.). Or perhaps directly from Old Norse gunnr "battle." The word was perhaps influenced by or confirmed by (or possibly from) Old French engon, dialectal variant of engin "engine."

Meaning grew with technology, from cannons to firearms as they developed 15c.; popularly applied to pistols and revolvers from 1744. In modern military use the word is restricted to cannons (which must be mounted), especially long ones used for high velocity and long trajectory. Hence great guns (1884 as an exclamation) distinguished from small guns (such as muskets) from c. 1400. Meaning "thief, rascal" is from 1858. For son of a gun, see son. To jump the gun (1912, American English) is a figurative use from track and field. Guns "a woman's breasts" (especially if prominent) attested by 2006.
[G]un covers firearms from the heaviest naval or siege guns (but in technical use excluding mortars and howitzers) to the soldier's rifle or the sportsman's shotgun, and in current U.S. use even the gangster's revolver. In the other European languages there is no such comprehensive word, but different terms for the small or hand gun of the soldier or sportsman (even these, sometimes differentiated) and the heavy naval guns or artillery pieces .... [Buck, 1949]
radon (n.)youdaoicibaDictYouDict
heaviest gaseous element, 1918, from German Radon, from radium (q.v.) + -on suffix of inert gases. The element was identified in radioactive decay of radium. Alternative name niton (from Latin nitens "shining") gained currency in France and Germany.