Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun perpetual_motion_machine

1 sense of perpetual motion machine

Sense 1
perpetual motion machine -- (a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy)
       => machine -- (any mechanical or electrical device that transmits or modifies energy to perform or assist in the performance of human tasks)