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

• knee-deep
• knee-drill
• knee-drills
• knee-high
• knee-highs
• knee-high to a grasshopper
• kneehole
• kneeholes
• knee-holly
• kneeing
• knee-jerk
• knee-jerks
• knee joint
• knee joints
• kneel
• kneeled
• knee-length
• kneeler
• kneelers
• kneeling
• kneels
• knee-pad
• knee-pads
• knee-pan
• knee-pans