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.
A hormone is a chemical substance. It's secreted by one tissue and travels by way of body fluids to affect another tissue in your body. In essence, hormones are chemical messengers.. Many hormones, especially those affecting growth and behavior, are significant to both men and women.