The American Heritage® Dictionary of the English Language, 4th Edition
n. A winglike structure attached to the hull of a boat that raises all or part of the hull out of the water when the boat is moving forward, thus reducing drag.
n. A boat equipped with hydrofoils. Also called hydroplane.
n. A wing attached to the hull of a ship that raises it out of the water when travelling at speed and thus reduces drag.
n. A vessel equipped with such a device.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds
n. a device consisting of a flat or curved piece (as a metal plate) so that its surface reacts to the water it is passing through
Word Usage
"However, by that time everybody had got used to the term hydrofoil, and nobody seemed to realize what a "wing-boat" was, so in the end the Språkråd voted to adopt hydrofoil as the officially recognized term."