a salt of hydrocyanic acid, 1826, from cyan-, used in science as a word-forming element for the carbon-nitrogen compound radical, + chemical ending -ide, on analogy of chloride. The best-known is potassium cyanide, bitter-tasting and extremely poisonous but formerly used in photography, electro-metallurgy, etc.
Proto-Indo-European root meaning "to shine;" it forms words for "gold" (the "bright" metal), words denoting colors, especially "yellow" and "green," also "bile, gall," for its color, and a large group of Germanic gl- words having to do with shining and glittering and, perhaps, sliding. Buck says the interchange of words for yellow and green is "perhaps because they were applied to vegetation like grass, cereals, etc., which changed from green to yellow."
It forms all or part of: arsenic; Chloe; chloral; chloride; chlorinate; chlorine; chloro-; chloroform; chlorophyll; chloroplast; cholecyst; choler; cholera; choleric; cholesterol; cholinergic; Cloris; gall (n.1) "bile, liver secretion;" gild; glad; glance; glare; glass; glaze; glazier; gleam; glee; glib; glide; glimmer; glimpse; glint; glissade; glisten; glister; glitch; glitter; glitzy; gloaming; gloat; gloss (n.1) "glistening smoothness, luster;" glow; glower; gold; guilder; jaundice; melancholic; melancholy; yellow; zloty.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit harih "yellow, tawny yellow," hiranyam "gold;" Avestan zari "yellow;" Old Persian daraniya-, Avestan zaranya- "gold;" Greek khlōros "greenish-yellow color," kholos "bile, gall, wrath;" Latin helvus "yellowish, bay," Gallo-Latin gilvus "light bay;" Lithuanian geltonas "yellow;" Old Church Slavonic zlutu, Polish żółty, Russian zeltyj "yellow;" Latin galbus "greenish-yellow," fellis "bile, gall;" Lithuanian žalias "green," želvas "greenish," tulžis "bile;" Old Church Slavonic zelenu, Polish zielony, Russian zelenyj "green;" Old Irish glass, Welsh and Breton glas "green," also "gray, blue;" Old English galla "gall, bile," geolu, geolwe, German gelb, Old Norse gulr "yellow;" Old Church Slavonic zlato, Russian zoloto, Old English gold, Gothic gulþ "gold;" Old English glæs "glass; a glass vessel."
name for salt formerly much used in pharmacy and old chemistry, late 14c., from Old French sal, from Latin sal (genitive salis) "salt" (from PIE root *sal- "salt"). For sal ammoniac "ammonium chloride" (early 14c.), see ammonia. Sal volatile, "ammonium carbonate," especially as used in reviving persons who have fainted, is by 1650s, Modern Latin, literally "volatile salt" (see volatile).
volatile alkali, colorless gas with a strong pungent smell, 1799, coined in scientific Latin 1782 by Swedish chemist Torbern Bergman as a name for the gas obtained from sal ammoniac, salt deposits containing ammonium chloride found near temple of Jupiter Ammon (from Egyptian God Amun) in Libya (see Ammon, and compare ammoniac). The shrine was ancient already in Augustus' day, and the salts were prepared "from the sands where the camels waited while their masters prayed for good omens" [Shipley], hence the mineral deposits. Also known as spirit of hartshorn and volatile alkali or animal alkali.
Old English sealt "salt, sodium chloride, abundant substance essential to life, used as a condiment and meat preservative," from Proto-Germanic *saltom (source also of Old Saxon, Old Norse, Old Frisian, Gothic salt, Dutch zout, German Salz), from PIE root *sal- "salt."
Applied from early 14c. to various substances resembling common salt. Modern chemistry sense "compound of an acid radical with a base radical" is from 1790; as an ultimate element in alchemy from 1580s. Meaning "experienced sailor" is attested by 1840 (Dana), probably a reference to the salinity of the sea. By 1570s as "that which gives piquancy to discourse or writing or liveliness to a person's character."
Salt long was regarded as having power to repel spiritual and magical evil. Many metaphoric uses reflect that this was once a rare and important resource, such as worth one's salt "efficient, capable" (1830), salt of the earth "persons of worthiness" (Old English, after Matthew v.13). Belief that spilling salt brings bad luck is attested from 16c. To be above (or below) the salt (1590s) refers to customs of seating at a long table according to rank or honor, and placing a large salt-cellar in the middle of the dining table.
Salt-shaker is from 1882. Salt-and-pepper (adj.) "of dark and light color" is by 1915 (pepper-and-salt, 1774, was an old name for a kind of cloth made from dark and light colored wools woven together). To take something with a grain of salt "accept with a certain amount of reserve" is from 1640s, from Modern Latin cum grano salis. The notion is perhaps "modification," hence "allowance, abatement, reserve."