1. chemistry corrosive substance: a sour-tasting compound that releases hydrogen ions to form a solution with a pH of less than 7, reacts with a base to form a salt, and turns blue litmus red. See also alkali (sense 1)
2. chemistry compound forming covalent bond with base: a compound that can donate a proton or accept a pair of electrons to form a covalent bond with a base
The Indo-European word from which acid is ultimately derived is also the ancestor of English acme, acrid, acrobat, acute, alacrity, eager, edge, oxygen, and vinegar.
