octennial /ok-tenˈyəl, -i-əl/

1. Happening every eighth year
2. Lasting eight years

• back-to-back
• back to basics
• back to earth
• back to front
• back to nature
• back-to-nature
• back to square one
• backtrack
• backtracked
• backtracking
• backtrackings
• backtracks
• back translation
• back translations
• back up
• back-up
• backup
• backup file
• backup files
• backup light
• backup lights
• backups
• backveld
• backvelder
• backvelders