Computers, Electronics. the complete path followed by a signal as it is fed back from the output of a circuit, device, or system to the input and then back to the output.
Engineering.
a processing system in which effluents are recycled, that is, treated and returned for reuse.
an automatic control system operating on a feedback principle.
a recursive concept, process, or system in which there is no beginning or end point, but rather the products of one phase become the materials for the next, whose products themselves are the materials for the original phase.
A circular economy is a closed loop, employing reuse, sharing, and remanufacturing to reduce waste.
Also called closed time loop. (in science fiction) a loop in space-time created by someone or something traveling back in time and setting in motion the events of the very timeline that leads to the time travel event, once again setting off events in the past that ultimately result in their being sent back in time, in an infinite, repeating loop.
Engineering.
of or relating to a processing system in which effluents are recycled, that is, treated and returned for reuse.
of or relating to an automatic control system operating on a feedback principle.
of or relating to a recursive concept, process, or system in which there is no beginning or end point, but rather the products of one phase become the materials for the next, whose products themselves are the materials for the original phase.
Around 75 percent of aluminum is kept out of landfills by closed-loop recycling, where used cans are pressed into ingots and rerolled into new cans, which can one day be recycled themselves.
First recorded in 1945–50
First recorded in 1950–55
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
A heat pump basically runs a chemical - the refrigerant - round and round in a closed loop, going from hot to cold, gas to liquid, compressed to decompressed.
From BBC ● Mar. 22, 2026
Not much happens, but the people are beautiful and so too are their bikes, rumbling beasts that tribe members ride and ride on that familiar closed loop known as Nowheresville, U.S.A.
From New York Times ● Jun. 20, 2024
It works by circulating liquid refrigerants with low boiling points through a closed loop, capturing warmth from the air.
From BBC ● Apr. 25, 2024
"We want to make it a closed loop by making the model into a real AI scientist," says Chen.
From Science Daily ● Mar. 8, 2024
So, one can regard the pair of particles as a single particle moving on a closed loop in space-time.
From "A Brief History of Time: And Other Essays" by Stephen Hawking
“With nearly 2.6 million subscribers across a diverse breadth of specialties, we have the scale to invest in technology and operations to leverage our closed-loop ecosystem,” Okupe said.
From The Wall Street Journal ● May 11, 2026
A "closed-loop" water cooling system, which works a bit like a car radiator and does not require regular refills, prevents them from malfunctioning.
From Barron's ● Feb. 26, 2026
The typical card you apply for at the register at the mall is often a closed-loop card, which can only be used at that retailer’s stores.
From MarketWatch ● Nov. 21, 2025
He said closed-loop cooling systems could increase energy use so Scottish Water were encouraging open-loop systems near wastewater treatment works.
From BBC ● Oct. 16, 2025
In their "closed-loop" system, drug concentrations can be continually monitored, and that information is used to automatically adjust the infusion rate of the chemotherapy drug and keep the dose within the target range.
From Science Daily ● Apr. 24, 2024
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
