regulator
Pluralregulators
- 1A device that controls or limits the flow, level, or operation of something.
The valve's regulator maintains a constant flow despite changes in supply pressure.
Engineers installed a regulator to keep the system from overheating.
Similarcontroller, governor
- 2A person or organization that sets standards of practice and enforces rules, especially under powers granted by law.
The environmental regulator ordered the factory to cut its emissions.
Regulators across Europe agreed on stricter safety standards for toys.
Similarwatchdog, authority, overseer
Note
The agent noun is transparent: regulate plus -or, one who regulates. It sits comfortably in the plural with a word naming the level of authority, as when Suzanne Rust writes in 2021 of earthquake risks "highlighted by federal regulators." The same formation gives the mechanical device, and context separates them: a regulator in this sense issues rules and enforces them, while a device simply limits a flow.
- 3Shortened form of voltage regulator.
The alternator's regulator maintains a steady output as engine speed changes.
Technicians replaced the regulator after the voltage spiked.
Note
Electronics talk drops the first word once the circuit is in view, so a voltage regulator becomes simply the regulator. The clipped form leans on that context. In writing, it reads best after the full compound has appeared once. The danger the device guards against is overvoltage, which can destroy whatever it feeds when the regulator fails.
- 4On a steam locomotive, the valve that sets how much steam is admitted to the cylinders.
Pulling back the regulator cut off steam to the cylinders and the locomotive coasted.
An experienced fireman watched as the driver opened the regulator on the long climb.
Similarthrottle
Note
On the footplate the regulator is something the driver opens, and how far it is opened sets the power. Balmore, writing in 1961 on driving and firing modern French steam locomotives, warns that too much regulator opening with a heavy train causes heavy slipping. A heavy train is therefore moved off very slowly. Open and opening are the verbs this sense keeps company with.
- 5In genetics, a gene that plays a part in controlling how one or more other genes are expressed.
The newly identified regulator suppresses several genes during embryonic development.
Mutations in the regulator can disrupt the timing of cell division.
Note
In genetics the regulator is defined by its relationships. It matters for what its product does to other genes, its targets, raising or lowering their expression within a network. A mutation in one can therefore ripple through every gene it controls. Unlike the mechanical device, it does not limit a flow; it switches downstream genes on or off.
- 6A highly accurate clock used by clockmakers as a standard against which to check the timekeeping of each newly made clock.
Each finished movement was compared to the regulator before it left the workshop.
The workshop's regulator stood in a sealed case to keep its rate constant.
- 7In algebraic number theory, a positive real number attached to a number field that measures how densely its units are spaced, as described by Dirichlet's unit theorem.
Computing the regulator of a number field requires finding a system of fundamental units.
For a real quadratic field, the regulator is the logarithm of the fundamental unit.
Note
Number theorists use it to measure a number field's unit group on a logarithmic scale. Take the logarithms of the sizes of a set of fundamental units and arrange them in a matrix. The regulator is the absolute value of its determinant, which is the volume of the lattice the units form. A larger regulator means the units lie more thinly. It sits beside the class number in the analytic class number formula.
- 8A member of an armed group of white Southerners in the United States who used intimidation and violence, especially during the Reconstruction era.
Bands of regulators terrorized freedmen who tried to vote that fall.
A notorious regulator was finally arrested after years of intimidation.
Similarbulldozer
Note
This is period vocabulary, best kept for writing about history rather than used as a living label. The name presents intimidation as keeping order, and that is worth signaling to readers with quotation marks or a brief gloss. Its partner term bulldozer belongs to the same setting. Both words now have everyday meanings, so make the context unmistakable: a regulator here is not the official rule-setter.
Practice
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Origin
Formed from the verb "regulate" with the suffix "-or."