Source : Webster's Revised Unabridged Dictionary (1913)

Biennial \Bi*en"ni*al\, n.
   1. Something which takes place or appears once in two years;
      esp. a biennial examination.

   2. (Bot.) A plant which exists or lasts for two years.

Biennial \Bi*en"ni*al\, a. [L. biennalis and biennis, fr.
   biennium a space of two years; bis twice + annus year. Cf.
   {Annual}.]
   1. Happening, or taking place, once in two years; as, a
      biennial election.

   2. (Bot.) Continuing for two years, and then perishing, as
      plants which form roots and leaves the first year, and
      produce fruit the second.

Source : WordNet®

biennial
     n : a plant having a life cycle that normally takes two seasons
         from germination to death to complete; flowering
         biennials usually bloom and fruit in the second season

biennial
     adj 1: occurring every second year; "they met at biennial
            conventions" [syn: {biyearly}]
     2: having a life cycle lasting two seasons; "a biennial life
        cycle"; "parsnips and carrots are biennial plants often
        grown as annuals" [syn: {two-year}] [ant: {perennial}, {annual}]