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. a chemical transmitter substance produced by cells of the body and transported by the bloodstream and other means to the cells and organs which carry specific receptors for the hormone and on which it has a specific regulatory effect.. A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism. 2. A synthetic compound that acts like a hormone in the body. horÂ·monâ²al (-mÅâ²nÉl) adj.