Naval Architecture. a surface form creating a thrust against water in a direction perpendicular to the plane approximated by the surface.
a winglike member having this form, designed to lift the hull of a moving vessel.
a vessel equipped with hydrofoils.

1915–20; hydro-1 + foil2

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World English Dictionary
hydrofoil (ˈhaɪdrəˌfɔɪl)
1.  a fast light vessel the hull of which is raised out of the water on one or more pairs of fixed vanes
2.  any of these vanes

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin & History

1920, "boat that travels through water on wings," formed in Eng. from hydro-, comb. form of Gk. hydor "water" (see water (n.1)) + foil (n.).
Online Etymology Dictionary, © 2010 Douglas Harper
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Encyclopedia Britannica


underwater fin with a flat or curved winglike surface that is designed to lift a moving boat or ship by means of the reaction upon its surface from the water through which it moves. Ships that use hydrofoils, or foils, are themselves called hydrofoils. Hydrofoils can lift a boat's hull clear of the water as speed increases, and the resultant reduction in drag yields higher speeds without expending more horsepower.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
After trying several designs, his engineers discovered the stepped hydrofoil
They may also be hovercraft, hydrofoil and other high-speed vessels.
Laboratory-scale testing will be done to investigate materials and coatings,
  hydrofoil performance, and small-scale array effects.
They may also be hovercraft, hydrofoil and other high speed vessels.
Related Words
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