Webster's Revised Unabridged Dictionary · 1913

Perennial

Perennial (per*en"ni*al) , adjective

[Latin perennis that lasts the whole year through; per through + annus year. See Per-, and Annual.]

1.
Lasting or continuing through the year; as, perennial fountains.
2.
Continuing without cessation or intermission; perpetual; unceasing; never failing.
The perennial existence of bodies corporate. — Burke
3.
(Botany) Continuing more than two years; as, a perennial steam, or root, or plant.

Perennial , noun

(Botany) A perennial plant; a plant which lives or continues more than two years, whether it retains its leaves in winter or not.