"small migratory bird of the Old World, noted for the male's melodious song, heard by night as well as day," Middle English nighte-gale, from Old English næctigalæ, in late Old English nihtegale, a compound formed in Proto-Germanic (compare Dutch nachtegaal, German Nachtigall) from *nakht- "night" (see night) + *galon "to sing," related to Old English giellan "to yell" (from PIE root *ghel- (1) "to call"). With parasitic -n- that began to appear mid-13c. Dutch nightingale "frog" is attested from 1769. In Japanese, "nightingale floor" is said to be the term for boards that creak when you walk on them.

French rossignol (Old French lousseignol) is, with Spanish ruiseñor, Portuguese rouxinol, Italian rosignuolo, from Vulgar Latin *rosciniola, a dissimilation of Latin lusciniola "nightingale," diminutive of luscinia "nightingale," which, according to de Vaan, "might be explained with haplology from *lusci-cania 'singing in the night' or 'blind singer', but this is speculative."

Old English giellan (West Saxon), gellan (Mercian) "to yell, sound, shout," class III strong verb (past tense geal, past participle gollen), from Proto-Germanic *gel- (source also of Old Norse gjalla "to resound," Middle Dutch ghellen, Dutch gillen, Old High German gellan, German gellen "to yell"), extended form of root of Old English galan "to sing" (source of the -gale in nightingale); from PIE root *ghel- (1) "to call." Intransitive sense from early 13c. Related: Yelled; yelling.

Old English gielpan (West Saxon), gelpan (Anglian) "to boast, exult," from Proto-Germanic *gel- (source also of Old Saxon galpon, Old Norse gjalpa "to yelp," Old Norse gjalp "boasting," Old High German gelph "outcry"), from PIE root *ghel- (1) "to call, cry out." Meaning "utter a quick, sharp, bark or cry" is 1550s, probably from the noun. Related: Yelped; yelping.

late 14c., "yellow arsenic, arsenic trisulphide," from Old French arsenic, from Latin arsenicum, from late Greek arsenikon "arsenic" (Dioscorides; Aristotle has it as sandarakē), adapted from Syriac (al) zarniqa "arsenic," from Middle Persian zarnik "gold-colored" (arsenic trisulphide has a lemon-yellow color), from Old Iranian *zarna- "golden" (from PIE root *ghel- (2) "to shine," with derivatives referring to bright materials and gold).

The form of the Greek word is folk etymology, literally "masculine," from arsen "male, strong, virile" (compare arseno-koites "lying with men" in New Testament) supposedly in reference to the powerful properties of the substance. As an element, from 1812. The mineral (as opposed to the element) is properly orpiment, from Latin auri pigmentum, so called because it was used to make golden dyes. Related: Arsenical.

... se lo pueden comer las hormigas o le puede caer en la cabeza una gran langosta de arsenico ... [Lorca, on the poet overmastered by intellect]

fem. proper name, Latin, from Greek Khloē, literally "young green shoot;" related to khlōros "greenish-yellow," from PIE *ghlo- variant of root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow."

"colorless liquid formed by the action of chlorine on alcohol," apparently coined by German chemist Justus von Liebig in 1833 from elements from chlorine + alcohol. Later chiefly in chloral hydrate (1874).

"compound of chlorine and another element," 1812, coined by Sir Humphry Davy from chlorine + -ide on the analogy of oxide.

"to combine or treat with chlorine," 1836 (implied in chlorinated), from chlorine (n.) + -ate (2). Related: Chlorinating.

nonmetallic element, the name coined 1810 by English chemist Sir Humphry Davy from Latinized form of Greek khlōros "pale green" (from PIE root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow") + chemical suffix -ine (2). Named for its color. Discovered 1774, but known at first as oxymuriatic acid gas, or dephlogisticated marine acid.

before vowels chlor-, word-forming element used in chemistry, usually indicating the presence of chlorine in a compound, but sometimes "green," from Latinized combining form of Greek khlōros "greenish-yellow" (from PIE root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow").