Definition of: biennial

(bī·en′ē·əl) adjective
1. Occurring every second year.
2. Lasting or living for two years.
—noun
1. Bot. A plant that produces leaves and roots the first year and flowers and fruit the second, then dies.
2. An event occurring once in two years. [<L biennis <bis twofold + annus year]
—bi·en′ni·al·ly adverb