1. a flat board or blade that can be raised or lowered through a slot in the hull of a sailboat to reduce sideways drift
Usage: nautical; also called a centerboard in some contexts

Examples

• The sailor lowered the daggerboard to improve the boat's stability in the wind.
• A daggerboard allows small sailboats to sail closer to the wind.
• The daggerboard was stuck, so the crew had to work to free it before setting sail.
• Unlike a fixed keel, a daggerboard can be retracted when sailing in shallow water.
• The daggerboard slot runs vertically through the center of the hull.