- any substance that retards deterioration by oxidation, esp of fats, oils, foods, petroleum products, or rubber
- a substance, such as vitamin C, vitamin E, or beta carotene, that counteracts the damaging effects of oxidation in a living organism
WordReference Random House Unabridged Dictionary of American English © 2015
- Chemistry[Chem.]any substance that inhibits oxidation, as a substance that inhibits oxidative deterioration of gasoline, rubbers, plastics, soaps, etc.
- Biochemistry[Biochem.]an enzyme or other organic substance, as vitamin E or beta carotene, that is capable of counteracting the damaging effects of oxidation in animal tissues.
- anti- + oxidant (oxid(ize) + -ant) 1925–30