fluoride /ˈflʊəˌɹaɪd/ noun3 •A binary compound of fluorine and another element or radical. •Any of certain salts of hydrofluoric acid, such as the simple metallic ones.However, too much fluoride produces a mottling effect on teeth. Large doses of fluoride are actually toxic. — 2000 •The anionic form of a fluorine atom. formsfluorides