Definitions:

1. A retaractable and vertically adjustable board that descends from the bottom of a sailboat or other watercraft to prevent the vessel from sliding sideways due to wind pressure against the sails. NOUN
   • In shallow waters, the daggerboard was raised to prevent it from hitting the bottom.
2. A type of retractable keel used in small sailing boats. NOUN
   • The sailor lowered the daggerboaed to improve the boat's stability and performance against the wind.
3. A vertical sliding board that can be raised or lowered to provide stability and reduce sidewasys drift while sailing. NOUN
   • The simplicity of the daggerboard system makes it easy for beginners to handle and understand.

Synonyms:

• centerboard
• drop keel
• retractable kee;
• sliding keel