1.Definition: 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

"The fins of a fish act as hydrofoils"

Related Noun(s):foil

Category: Objects

2.Definition: a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds

Related Noun(s):hydroplane

Category: Objects