1. Occurring once every 20 years

See also: twenty

• pill
• pill bottle
• pill bug
• pill head
• pill pusher
• pill roller
• pillage
• pillaged
• pillager
• pillaging
• pillar
• pillar box
• pillar of Islam
• pillar of strength
• pillar-box red
• pillar-shaped
• pillared
• Pillars of Hercules
• pillbox
• pillion
• pillock
• pillory
• pillow
• pillow block
• pillow fight