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.
The definition of a hormone is a chemical substance produced by an endocrine gland that has a specific effect on the activities of other organs in the body. The major female and male hormones can be classified as estrogens or androgens.he definition of a hormone is a chemical substance produced by an endocrine gland that has a specific effect on the activities of other organs in the body. The major female and male hormones can be classified as estrogens or androgens.