perennial

This is a neat little botanical time bomb. Romans had perennis, a word built from per, “through,” and annus, “year,” so the image is literally something that lasts year after year, like a stream that refuses to dry up. English grabbed it in the 1640s first for evergreen plants, then stretched it to anything persistent — a perennial headache, a perennial favorite. That makes it a cousin of annual and biennial, those tidy calendar words gardeners use to sort the plant world like a nursery ledger. Even the modern adjective still feels a bit smug, as if it knows the subject will outlast the season and probably your patience.