乙內
Hydantoin \Hy*dan"to*in\, n. [Hydrogen + allantion.] (Chem.) A derivative of urea, {C3H4N2O2}, obtained from allantion, as a white, crystalline substance, with a sweetish taste; -- called also {glycolyl urea}.
hydantoin n : any of a group of anticonvulsant drugs used in treating epilepsy