hormone

Any of numerous organic compounds that serve as chemical messengers. They are secreted by a gland or organ into the body fluids of an animal, particularly the bloodstream, by a gland or organ, are transported to another part of the organism, and trigger or regulate particular functions such as growth, metabolism, reproduction, and the functioning of various organs. The term may also refer to similar compounds produced by plants or produced synthetically. The term was coined in 1905 from the Greek "horman," meaning "to set in motion."