Merriam-Webster's Collegiate® Dictionary, 11th Edition
REGULATION
I. noun
Date: 1665
the act of regulating ; the state of being regulated,
2. an authoritative rule dealing with details or procedure , a rule or order issued by an executive authority or regulatory agency of a government and having the force of law,
3. the process of redistributing material (as in an embryo) to restore a damaged or lost part independent of new tissue growth, the mechanism by which an early embryo maintains normal development, see: law
II. adjective
Date: circa 1839
conforming to regulations ; official