Borrowed from Latin biennium [from bis, bi- ("twice") + annus ("year")] + -al.

• IPA: /baɪˈɛn.i.əl/

biennial (not comparable)

1. Happening every two years.
2. Lasting for two years.

• biennary (uncommon); biannual (proscribed)

• biennium
• biennially
• biannual, semiannual

• French: bisannuel, biennal
• German: biennal, zweijährlich
• Italian: biennale
• Portuguese: bienal
• Russian: двухгоди́чный
• Spanish: bienal

• French: biennal
• German: biennal, zweijährig
• Portuguese: bienal
• Russian: двухле́тний
• Spanish: bienal

biennial (plural biennials)

1. A plant that requires two years to complete its life-cycle, germinating and growing in its first year, then producing its flowers and fruit in its second year, after which it usually dies.
2. An event that happens every two years.
   • 1891, Sir George Chetwynd, Racing Reminiscences and Experiences of the Turf, page 122:

     The famous Biennial was won by Earl of Dartrey, a light, peacocky horse, who was, perhaps, better than he looked.

• French: bisannuelle

• Italian: biennale