octennial /ok-tenˈyəl, -i-əl/

1. Happening every eighth year
2. Lasting eight years

octennˈially adverb

• musers
• muses
• muset
• musette
• musettes
• museum
• museum beetle
• museum beetles
• museum piece
• museum pieces
• museums
• mush
• musha
• mushed
• musher
• mushers
• mushes
• mushier
• mushiest
• mushily
• mushiness
• mushinesses
• mushing
• mushmouth
• mush-mouthed