perennial (adj.)

1640s, "evergreen," formed in English from Latin perennis "lasting through the year (or years)," from per "through" (from PIE root *per- (1) "forward," hence "through") + annus "year" (see annual (adj.)). Botanical sense of "Remaining alive through a number of years" is attested from 1670s; figurative meaning of "enduring, permanent" is from 1750. Related: Perennially. For vowel change, see biennial. The noun meaning "a perennial plant" is from 1763.