What does arrestor mean?
An arrestor is a noun denoting a device designed to stop, check, or divert some form of movement or flow — most commonly electrical surges, sparks, or flames. It functions as a less frequent variant spelling of "arrester," though it is firmly established in certain technical fields: engineers speak of lightning arrestors on power lines, spark arrestors on chimneys and exhaust systems, and flame arrestors in pipelines carrying flammable gases. The word carries no figurative or everyday connotations; outside engineering, plumbing, and electrical work it is rarely encountered. Its value lies in precision — naming the specific hardware whose job is safety, whether that means giving a lightning strike a harmless path to earth or preventing burning embers from leaving a woodstove. Writers should note that style guides and industry documents vary between "arrestor" and "arrester," so consistency within a document matters more than choosing one over the other.
nounA device or mechanism that stops, checks, or impedes movement or the flow of something, such as electricity, flame, or mechanical motion. It is a variant spelling of "arrester," used chiefly in technical and engineering contexts.
- A device that halts or diverts a flow or current, especially electrical surges (e.g., a lightning arrestor).
- A mechanical component that stops or limits movement of machinery or parts.
"The electrician installed a lightning arrestor to protect the building's wiring from power surges."
"Each chimney was fitted with a spark arrestor to prevent embers from escaping into the dry forest."
"The surge arrestor tripped during the storm, sparing the server room from a catastrophic voltage spike."
Regular plural; both "arrestors" and "arresters" appear in technical literature depending on spelling convention.
"All three arrestors were inspected during the annual maintenance check."
A lightning arrestor doesn't stop lightning from striking — it gives millions of volts a safe path to the ground so your electronics survive.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of arrestor
The word derives from "arrest," which entered English from Old French "arester," itself from Latin "arrestare" — formed from Latin "ad-" ("to") plus "restare" ("to stand still"), literally meaning "to bring to a stand." The suffix "-or," from the Latin agentive ending "-or," forms nouns denoting an instrument or agent, so an arrestor is literally "that which brings to a stand." The spelling with -or reflects Latinate influence and parallels other technical terms like "governor" and "regulator."
Related word forms
How arrestor is actually used
"Arrestor" appears almost exclusively in technical, engineering, and electrical contexts. In general prose and in many manufacturers' literature, "arrester" is the more standard spelling; both are accepted, but writers should follow the convention of their field or product documentation.
Easily confused with arrestor
"Arrester" is the more common spelling of the same device (as in lightning arrester), while "arrestor" is an accepted but less frequent variant.
"Arrest" is the act of stopping or seizing something (especially by police), whereas "arrestor" is the noun for a device that performs such stopping in technical contexts.