ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ noun
( -s )
Etymology: center (I) + board
1. in a shallow-draft sailing vessel : a device (as a broad board or slab of wood or metal pivoted at its forward lower corner) in a casing or trunk amidships so that it may be raised either in shallow water or when the vessel is beached or lowered to increase the area of lateral resistance and prevent leeway when the vessel is working to windward or sailing wind abeam — called also drop keel, sliding keel
2. also center boarder
[short for centerboard boat ]
: a boat with a centerboard