sexennial /sek-senˈyəl or -senˈi-əl/

1. Lasting six years
2. Recurring every six years

sexennˈially adverb

• boatswain's chair
• boatswain's chairs
• boatswain's mate
• boatswain's mates
• boatswain's pipe
• boatswain's whistle
• boattail
• boattails
• boat train
• boat trains
• bob
• boba
• bobac
• bobacs
• Bobadil
• bobak
• bobaks
• bob-apple
• bob-apples
• bobas
• bobbed
• bobber
• bobberies
• bobbers
• bobbery