Bī-ĕn'ni-al1, a.
a. [Lat. biennalis and biennis; biennium, a space of two years; bis, twice, and annus, year.] 1. Happening, or taking place, once in two years; as, a biennial election. 2. (Bot.) Continuing for two years, and then perishing, as plants whose roots and leaves are formed the first year, and which produce fruit the second.