regulator

noun

1. a person or thing that regulates.
2. Horology.
   1. an adjustable device in a clock or a watch for making it go faster or slower.
   2. a master clock, usually of great accuracy, against which other clocks are checked.
3. Machinery.
   1. a governor mechanism for regulating the flow of fuel, steam, etc., to an engine in order to maintain constant speed under varying load or resistance.
   2. a valve for regulating the pressure of flowing gas or liquid to maintain a predetermined pressure.
   3. any of various mechanisms for maintaining a temperature, a level of liquid in a tank, etc.
4. Electricity. a device for maintaining a designated characteristic, as voltage or current, at a predetermined value, or for varying it according to a predetermined plan.
5. a device on scuba equipment for regulating the rate at which compressed air is fed through a breathing tube in proportion to the depth of water.
6. a device for maintaining a constant gas pressure.
7. (initial capital letter) American History.
   1. a member of any of several bands or committees in North Carolina (1767–71), formed to resist certain abuses, as extortion by officials.
   2. (in newly settled areas) a member of any band or committee organized to preserve order before the establishment of regular legal authority.

noun

1. a person or thing that regulates
2. the mechanism, including the hairspring and the balance wheel, by which the speed of a timepiece is regulated
3. a timepiece, known to be accurate, by which others are timed and regulated
4. any of various mechanisms or devices, such as a governor valve, for controlling fluid flow, pressure, temperature, voltage, etc
5. Also called: regulator gene a gene the product of which controls the synthesis of a product from another gene