noun
: a substance (as a vitamin, hormone, antibiotic, or metallic ion) exclusive of those used as sources of energy that when present in minute amounts promotes the growth of an organism — compare growth regulator
noun
: a substance (as a vitamin, hormone, antibiotic, or metallic ion) exclusive of those used as sources of energy that when present in minute amounts promotes the growth of an organism — compare growth regulator
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012