vicennial /vī-senˈyəl/

1. Lasting, or coming at the end of, twenty years
2. Occurring every twenty years

• sand dab
• sand dabs
• sand dance
• sand dances
• sand-dart
• sand-darts
• sand-devil
• sand-devils
• sand dollar
• sand dollars
• sand-dune
• sand-dunes
• sanded
• sand eel
• sand eels
• Sandemanian
• sander
• sanderling
• sanderlings
• sanders
• sanderses
• sanderswood
• sanderswoods
• sand-flag
• sand-flags