pĕrennĭtas — Lewis & Short
pĕrennĭtas, ātis, f.id.,
I lastingness, continuance, perpetual duration, perpetuity (class.):
fontium perennitates,Cic. N. D. 2, 39, 98:
cibi,constant food, Plaut. Pers. 3, 1, 2:
perennitatem conditis frumentis afferunt,Col. 1, 6, 10:
vitae,Ambros. in Psa. 118, Serm. 13, 22: Perennitas, a title of the Roman emperors:
vestra,your perpetuity, your perennity, Symm. Ep. 10, 45; Sex. Ruf. Brev. 2.