Pronunciation: (reg"yu-lā'shun),[key] —n. 1. a law, rule, or other order prescribed by authority, esp. to regulate conduct.
2. the act of regulating or the state of being regulated.
3. Mach.the percentage difference in some quantity related to the operation of an apparatus or machine, as the voltage output of a transformer or the speed of a motor, between the value of the quantity at no-load operation and its value at full-load operation.
4. Electronics.the difference between maximum and minimum voltage drops between the anode and the cathode of a gas tube for a specified range of values of the anode current.
5. Sports.the normal, prescribed duration of a game according to the sport's regulations, exclusive of any extra innings, overtime period, etc.: The Knicks tied the score in the final seconds of regulation, sending the game into overtime.
—adj. 1. prescribed by or conforming to regulation: regulation army equipment. 2. usual; normal; customary: the regulation decorations for a Halloween party.