n. The adjustable keel on a small yacht or dinghy that acts, among other things, as ballast and to counteract the sideways force of the wind.
the GNU version of the Collaborative International Dictionary of English
n. same as centerboard.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a retractable fin keel used on sailboats to prevent drifting to leeward
Word Usage
"I pulled up my centreboard, ran full tilt into the mud, took in sail, and, standing in the stern, as I had often done at low tide, I began to shove the skiff with an oar."