Freebase(0.00 / 0 votes)Rate this definition: Hydroelectricity. Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water.
Definition: Hormones. Hormones. Hormones are chemical substances that act like messenger molecules in the body. After being made in one part of the body, they travel to other parts of the body where they help control how cells and organs do their work. For example, insulin is a hormone that's made by the beta cells in the pancreas.
Hormone definition, Biochemistry. any of various internally secreted compounds, as insulin or thyroxine, formed in endocrine glands, that affect the functions of specifically receptive organs or tissues when transported to them by the body fluids. Pharmacology. a synthetic substance used in medicine to act like such a compound when introduced into the body.