perpetual-motion machine

Cultural  

1. A machine that could run forever. A perpetual-motion machine would have to produce at least as much energy as was needed for its operation. According to the second law of thermodynamics, such a machine is impossible, and to date none has ever been successfully demonstrated.

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Example Sentences

His White House was a perpetual-motion machine, reaching into every corner of Washington and beyond.

From The Wall Street Journal • Dec. 24, 2025

Now, if you have systems that spontaneously want to move, this sounds dangerously like a perpetual-motion machine, and that had scared physicists away.

From Scientific American • May 11, 2022

Seattle has been so rich in a diversified and high-end economy that it seemed a perpetual-motion machine.

From Seattle Times • Nov. 12, 2021

A perpetual-motion machine, Havlicek earned a reputation as the pre-eminent hustle player of his time as he repeatedly wore out his opponents with tireless and unmatched baseline-to-baseline efforts.

From Reuters • Apr. 24, 2020

For instance, thermodynamics tells you that it is impossible to create a perpetual-motion machine.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife