| Noun | 1. | hydrofoil - 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" Synonyms: foil |
| 2. | hydrofoil - a speedboat that is equipped with hydrofoils that lift it so that it skims the water at high speeds; "the museum houses a replica of the jet hydroplane that broke the record" Synonyms: hydroplane |