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[hahy-druh-foil] /ˈhaɪ drəˌfɔɪl/
Naval Architecture. a surface form creating a thrust against water in a direction perpendicular to the plane approximated by the surface.
  1. a winglike member having this form, designed to lift the hull of a moving vessel.
  2. a vessel equipped with hydrofoils.
1915-20; hydro-1 + foil2 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for hydrofoil
  • After trying several designs, his engineers discovered the stepped hydrofoil hull.
  • 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.
  • The report investigated the advantages of using basic airfoil or hydrofoil research in the field of floating breakwaters.
British Dictionary definitions for hydrofoil


a fast light vessel the hull of which is raised out of the water on one or more pairs of fixed vanes
any of these vanes
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for hydrofoil

1959, "boat that travels through water on wings," short for hydrofoil boat, originally the name of the "wings" themselves (1920); formed in English from hydro- + foil (n.).

Online Etymology Dictionary, © 2010 Douglas Harper
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Encyclopedia Article for hydrofoil

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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