An Etymological Dictionary of Astronomy and Astrophysics

Lasting an indefinitely long time; eternal; permanent. → perpetual motion; → perpetual calendar.

Etymology (EN): M.E. perpetuall, from O.Fr. perpetuel, from L. perpetualis “permanent,” from perpetuus “continuous, universal,” from perpetis, genitive of Old L. perpes “lasting;”

Etymology (PE): Hamišegi from hamišé “always;” Mid.Pers. hamišag, from anôšag “immortal,” from Av. an-aoša-, from negation prefix → an- + aošah- “death; ruin; corruption” (Mid.Pers. hôš “death;” Mod.Pers. hôš, huš “death; mind; intellect”); cf. derivatives Sogd. nôšé “immortal,” nôšak “always;” Mod.Pers. nôš, nuš “the water of immortality; sweet; honey.”