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

• rollers
• roller skate
• roller-skate
• roller-skated
• roller-skater
• roller-skaters
• roller skates
• roller-skates
• roller-skating
• roller towel
• roller towels
• rollick
• rollicked
• rollicking
• rollickings
• rollicks
• roll in
• rolling
• rolling hitch
• rolling hitches
• rolling in the aisles
• rolling launch
• rolling launches
• rolling mill
• rolling mills