Merriam-Webster Collegiate Dictionary - regulation

 I. noun  Date: 1665  1. the act of regulating ; the state of being regulated  2.  a. an authoritative rule dealing with details or procedure safety ~s  b. a rule or order issued by an executive authority or regulatory agency of a government and having the force of law  3.  a. the process of redistributing material (as in an embryo) to restore a damaged or lost part independent of new tissue growth  b. the mechanism by which an early embryo maintains normal development  Synonyms: see law  II. adjective  Date: circa 1839 conforming to ~s ; official