What is "quaternary ammonium compound"

n. (context chemistry English) An amine derivative, containing four radicals, of general formula R₁R₂R₃R₄-N⁺X^-; the radicals may be the same, different, or part of a ring; X is any univalent anion such as OH^-.

n. a compound derived from ammonium with hydrogen atoms replaced by organic groups; used as surface-active agents, disinfectants, and in drugs