Meaning

noun (botany) a plant lasting for three seasons or more

adjective lasting three seasons or more

adjective lasting an indefinitely long time; suggesting self-renewal

originThe adjective is borrowed from Latin perennis (“lasting through the whole year or for several years, perennial; continual, everlasting, perpetual”) + English -al (suffix meaning ‘of or pertaining to’ forming adjectives). Perennis is derived from per- (“completive or intensifying prefix with the sense of doing something all the way through or entirely”) + annus (“year; season, time”) (possibly…

Etymology from Wiktionary, CC BY-SA 3.0