What does hydrofoil mean?
A hydrofoil is a vessel that rises above the water on wing-like lifting surfaces. Unlike a conventional boat, which displaces water as it moves, a hydrofoil uses submerged wings to create upward lift, reducing drag and allowing relatively high speeds with less disturbance. The same term can also refer to an individual lifting surface rather than the entire vessel. As a verb, “hydrofoil” means to travel or ride on such a craft, though this use is uncommon outside technical contexts. Hydrofoils are associated especially with fast passenger ferries, military vessels, and recreational craft. The name combines “hydro-,” referring to water, with “foil,” a lifting surface in aeronautics and engineering. The term is distinct from “hydroplane,” which describes a craft intended to skim over the water primarily on its hull rather than on submerged lifting wings.
A vessel that rises above the water on lifting surfaces, or one of the submerged wing-like surfaces that produces that lift.
"The new hydrofoil reduced its speed as it entered the harbor."
The term may denote either the complete vessel or an individual lifting surface, depending on context.
To travel or ride on a hydrofoil.
"They hydrofoiled across the bay during the festival."
This use is uncommon in general speech; “travel by hydrofoil” is often more natural.
The plural may refer to multiple vessels or to multiple individual lifting surfaces.
"The harbor's hydrofoils carried thousands of passengers each day."
A hydrofoil flies underwater: its submerged wings turn a conventional hull into a craft that races above the waves.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does hydrofoil come from?
“Hydrofoil” combines the combining form “hydro-,” from Greek hydōr, meaning “water,” with “foil,” a technical term for a wing-like surface that produces lift. The compound is associated with early 20th-century experiments and development of watercraft capable of rising above the surface at speed. Its “hydro-” element ultimately derives from the same Greek root found in words such as hydrogen and hydrocarbon.
How hydrofoil is actually used
The word is chiefly technical and maritime. In the verb form, it is less common than “travel by hydrofoil” and may sound formal or specialized.
Easily confused with hydrofoil
A hydrofoil uses submerged or partly submerged wings to generate lift, whereas a hydroplane is designed chiefly to skim over the water on its hull.