• In software development, The Regulator is a free program that helps the developer create Regular Expressions in a more visual way.
• In scuba diving, a diving regulator provides a diver with breathing gas at ambient pressure from a diving cylinder.
• The related gas pressure regulator is a device that is attached to propane, acetylene or butane cylinders to provide a workable low-pressure gas stream from which equipment can be safely operated.
• In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. For example, a voltage regulator maintains a constant voltage when the input is variable.
• In a steam locomotive a regulator is the lever and associated valve which controls the passage of steam from the boiler to the cylinders.
• In social science, a regulator is an official responsible for control and supervision of an activity or area of public interest.
• In algebraic number theory, the regulator of a number field is a quantity defined from the group of units. After taking logarithms, it has the interpretation of the volume of a fundamental domain in the lattice of units in 'logarithmic space'.
• In physics, a regulator is a construction used in regularization techniques.
• A battery regulator is a device in a battery pack which bleeds off excess charge current to let all cells reach full charge without overcharging some cells.
• In the British Royal Navy, a Regulator is a naval policeman (or woman), a member of the Royal Navy Regulating Branch.

Regulators may refer to:-

• A regulatory agency, a body that enforces the regulations. See for example competition regulator.
• Members of the Regulator movement, a small-scale rebellion in North Carolina during the 1760s
• Members of Shays' Rebellion in 1786, also known as Shaysites
• A posse formed during the Lincoln County War in the late 1870s. One of its members was Billy the Kid
• The Regulators, a novel written under Stephen King's pen name, Richard Bachman

Algebraic number theory