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

• oliphant
• oliphants
• olitories
• olitory
• olivaceous
• olivary
• olivary bodies
• olive
• olive-back
• olive-backs
• olive branch
• olive branches
• olive drab
• olive-drab
• olive green
• olive-green
• olivenite
• olivenites
• olive oil
• olive oils
• oliver
• Oliver
• Oliverian
• olivers
• olives