from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of several structures that project from the side of a boat or ship, especially a gun platform.
- n. A short, curved, air-filled projection on the hull of a seaplane, imparting stability in the water.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A projection from the side of a watercraft.
from the GNU version of the Collaborative International Dictionary of English
- n. One of the triangular platforms in front of, and abaft, the paddle boxes of a steamboat.
- n. One of the slanting supports under the guards of a steamboat.
- n. One of the armored projections fitted with gun ports, used on modern war vessels.
from The Century Dictionary and Cyclopedia
- n. Nautical, the curve of the timbers and planking toward the outer part of the wing, before and abaft each of the paddle-boxes of a steamer; also, the framework itself.
- n. In a war-ship, a projecting structure in which a gun is placed: designed to enable the gun to be trained forward and aft.
- In ship-building, to be fitted with a sponson, or to have a projection from the side of a vessel of the form of a sponson: usually followed by out.
Perhaps alteration of expansion.(American Heritage® Dictionary of the English Language, Fourth Edition)