biennial /bī-enˈi-əl or -enˈyəl/

1. Lasting two years
2. Happening or appearing once in two years

1. A plant that flowers and fruits only in its second year, then dies
2. An event taking place or being celebrated every two years

biennˈially adverb

• unidentifiable
• unidentified
• unidiomatic
• unidiomatically
• unidirectional
• UNIDO
• unifiable
• unific
• unification
• Unification Church
• unifications
• unified
• unified field
• unified fields
• unified scale
• unified scales
• unifier
• unifiers
• unifies
• Unifil
• unifilar
• uniflorous
• unifoliate
• unifoliolate
• uniform