名詞 biennial:

1. 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

形容詞 biennial:

1. occurring every second year
   同義詞：biyearly
2. having a life cycle lasting two seasons
   同義詞：two-year

bi.en.ni.al

adj.（形容詞）
Lasting or living for two years.
持續(xù)兩年的，生活兩年的
Happening every second year.
每兩年發(fā)生一次的
Botany Having a life cycle that normally takes two growing seasons to complete.
【植物學】 二年生的：需要兩個生長季來完成生命周期的
n.（名詞）
An event that occurs every two years.
每兩年發(fā)生一次的事
Botany
【植物學】
A plant that normally requires two seasons to complete its life cycle, growing usually as a rosette in the first season and producing flowers and fruits and then dying in the second season.
二年生植物：一般需要兩個生長季來完成其生命周期的植物，通常是第一季生長為蓮座叢，第二季開花、結果，后死亡
A perennial plant, such as the English daisy, cultivated as a biennial.
以兩年生植物栽種的多年生植物，如英國雛菊

【引伸】
bien.nially
adv.（副詞）