An act or state of something causing itself to continue to exist.

plural of self-perpetuation

plural of perpetual bond

(Internet slang) Synonym of Eternal September

(accounting) A system of maintaining a business' inventory in which changes to the inventory are recorded in real time, so that the inventory is always accurate.

plural of perpetual license

(physics, pseudoscience) A hypothetical device that exhibits perpetual motion, especially one that does useful work with no input of energy.

plural of perpetual motion machine

plural of rule against perpetuities

(law, singular only) The rule that prevents a testator or other transferor of property from controlling further transfer of his property more than twenty-one years after the death of anyone alive at the time of the original transfer who may have some interest in the transfer.