toxins definition
Full Definition of TOXIN. : a poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation. See toxin defined for English-language learners.See toxin defined for kids. a poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation. See toxin defined for English-language learners. See toxin defined for kids.