adj. 1 eternal; lasting for ever or indefinitely. 2 continuous, uninterrupted. 3 colloq. frequent, much repeated (perpetual interruptions). 4 permanent during life (perpetual secretary). perpetual calendar a calendar which can be adjusted to show any combination of day, month, and year. perpetual check Chess the position of play when a draw is obtained by repeated checking of the king. perpetual motion the motion of a hypothetical machine which once set in motion would run for ever unless subject to an external force or to wear. perpetualism n. perpetually adv.
[ ME f. OF perpetuel f. L perpetualis f. perpetuus f. perpes -etis continuous ]