salt

A common substance, chemically consisting mainly of sodium chloride (NaCl), used extensively as a condiment and preservative.

(chemistry) One of the compounds formed from the reaction of an acid with a base, where a positive ion replaces a hydrogen of the acid.

(uncommon) A salt marsh, a saline marsh at the shore of a sea.

(slang) A sailor (also old salt).

(cryptography) Randomly chosen bytes added to a plaintext message prior to encrypting or hashing it, in order to render brute-force decryption more difficult.

A person who seeks employment at a company in order to (once employed by it) help unionize it.

(obsolete) Flavour; taste; seasoning.

(obsolete) Piquancy; wit; sense.

(obsolete) A dish for salt at table; a salt cellar.

(historical, in the plural) Epsom salts or other salt used as a medicine.

(figuratively) Skepticism and common sense.

(Internet slang) Tears; indignation; outrage; arguing.

(UK, historical) The money demanded by Eton schoolboys during the montem.