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Webster 1913 Edition

(lē′bōrdˊ)

Noun.

A board, or frame of planks, lowered over the side of a vessel to lessen her leeway when closehauled, by giving her greater draught.

leeboard ‎(plural leeboards)

(nautical) A board, or frame of planks, lowered over the side of a sailboat to lessen its leeway.