Meaning of leeboard

lee•board

Pronunciation: (lē'bôrd", -bōrd"), [key]
— n. Naut.
  1. either of two broad, flat objects attached to the sides of a sailing ship amidships, the one on the lee side being lowered into the water to prevent the ship from making leeway.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.