adj. & n.
adj. 1 lasting through a year or several years. 2 (of a plant) lasting several years (cf. ANNUAL). 3 lasting a long time or for ever. 4 (of a stream) flowing through all seasons of the year.
n. a perennial plant (a herbaceous perennial). perenniality n. perennially adv.
[ L perennis (as PER-, annus year) ]