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

• blue riband
• blue ribands
• blue ribbon
• Blue Ribbon Army
• blue ribbons
• blue rinse
• blue-rinse
• blue-rinsed
• blue rinsers
• blue rinses
• blue rocket
• blue-rot
• blue-rots
• blue ruin
• blue ruins
• blues
• blue screen
• blue-screen
• blue screens
• blue shark
• blue sharks
• blue sheep
• bluesier
• bluesiest
• blue-skies