<p><strong>Noun</strong></p><ul><li>A law, rule, or other order prescribed by authority, especially to regulate conduct: Safety regulations require the use of impact-resistant helmets.</li><li>The act of regulating or the state of being regulated: Adolescence is a potentially important time in the development of emotion regulation.</li><li>Synonyms: adjustment, disposition, dispensation, management, direction.</li><li>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.</li><li>Biology: the internal response that an organism undergoes to adapt to external stimuli: Regulation of blood flow is an essential mechanism for delivering oxygen and glucose to the tissues that need it most.</li><li>Genetics: the act or process of controlling the expression of genes: Scientists are hoping to discover whether viruses can be used to study gene regulation in mammalian cells.</li><li>Embryology: the process by which an embryo can continue to develop normally after it has been damaged: Added cells become normally integrated into the body of the host embryo, which provides additional evidence of embryonic regulation.</li><li>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.</li><li>Machinery: 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.</li></ul><p><strong>Adjective</strong></p><ul><li>Prescribed by or conforming to regulation: regulation army equipment.</li><li>Usual; normal; customary: the regulation decorations for a Halloween party.</li><li>Sports: during the normal, prescribed duration of a game: Both teams are entitled to two timeouts in each half of regulation play.</li></ul>