Old English sealt "salt" (n.; also as an adjective, "salty, briny"), from Proto-Germanic *saltom (cf. Old Saxon, Old Norse, Old Frisian, Gothic salt, Dutch zout, German Salz), from PIE *sal- "salt" (cf. Greek hals "salt, sea," Latin sal, Old Church Slavonic soli, Old Irish salann, Welsh halen "salt").
Modern chemistry sense is from 1790. Meaning "experienced sailor" is first attested 1840, in reference to the salinity of the sea. Salt was long regarded as having power to repel spiritual and magical evil. Many metaphoric uses reflect that this was once a rare and important resource, e.g. worth one's salt (1830), salt of the earth (Old English, after Matt. 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-lick first recorded 1751; salt-marsh is Old English sealtne mersc; salt-shaker is from 1882. Salt-and-pepper "of dark and light color" first recorded 1915. To take something with a grain of salt is from 1640s, from Modern Latin cum grano salis.
Old English sealtan, from Proto-Germanic *salto- (see salt (n.)), and in part from the noun. Related: Salted; salting.
Cold War U.S.-U.S.S.R. nuclear weapons negotiations, 1968, acronym for Strategic Arms Limitation Talks (which would make SALT talks redundant, but the last element sometimes also is understood as treaty).
A colorless or white crystalline solid, chiefly sodium chloride, used extensively as a food seasoning and preservative.
A chemical compound replacing all or part of the hydrogen ions of an acid with metal ions or electropositive radicals.
salts Any of various mineral salts, such as magnesium sulfate, sodium sulfate, or potassium sodium tartrate, used as laxatives or cathartics.
salts Smelling salts.
salts Epsom salts.
Worth one's salary (a word that comes from the Latin for salt) or wages. From the Roman custom of paying soldiers money to buy salt.
Worth what it costs to keep: anyone worth their salt will be kept