perpetual-motion machine
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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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Which of the following nouns has an irregular plural form?
Words nearby perpetual-motion machine
perpetual check, perpetual debenture, perpetual inventory, perpetually, perpetual motion, perpetual-motion machine, perpetuate, perpetuation, perpetuity, perphenazine, Perpignan
The New Dictionary of Cultural Literacy, Third Edition
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