adjective

1. lasting or active throughout the whole year
2. lasting or continuing for a long time perennial youth
3. returning or becoming active again and again; perpetual
4. having a life cycle of more than two years: said esp. of herbaceous plants that produce flowers and seed from the same root structure year after year

Etymology: < L perennis, lasting through the year < per-, through + annus, a year: see per & annual

noun

1. a perennial plant
2. a person or thing that is present continuously or reappears regularly