closed loop

¹

[ klohzd loop ]

noun

1. 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. Compare feedback loop.
2. Engineering.
   1. a processing system in which effluents are recycled, that is, treated and returned for reuse.
   2. an automatic control system operating on a feedback principle.
3. 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.

4. 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.

closed-loop

²

[ klohzd-loop ]

adjective

1. Engineering.
   1. of or relating to a processing system in which effluents are recycled, that is, treated and returned for reuse.
   2. of or relating to an automatic control system operating on a feedback principle. feedback ( def 2 ).
2. 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.

Word History and Origins

Origin of closed loop¹

First recorded in 1945–50

Origin of closed loop²

First recorded in 1950–55

Example Sentences

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

The Sagnac effect occurs when light traveling in opposite directions around a closed loop exhibits different travel times.

From Science Daily

Creating a "closed loop" fuel based on existing emissions would eliminate the need for traditional and sustainable jet fuels, which add further emissions into the atmosphere.

From Science Daily

It works by circulating liquid refrigerants with low boiling points through a closed loop, capturing warmth from the air.

From BBC

Ring polymers are macromolecules composed of repeating units, forming closed loops without free ends.

From Science Daily