duodecennial /dū-ō-di-senˈyəl/

Occurring every twelve years

• spicileges
• spicily
• spiciness
• spicinesses
• spicing
• spick
• spick and span
• spick and span new
• spicker
• spickest
• spicknel
• spicks
• spics
• spicula
• spiculae
• spicular
• spiculate
• spicule
• spicules
• spiculum
• spicy
• spide
• spider
• spider beetle
• spider beetles