/huy"dreuh foyl'/ , n.
1. Naval Archit. a surface form creating a thrust against water in a direction perpendicular to the plane approximated by the surface.
2. Naut.
a. a winglike member having this form, designed to lift the hull of a moving vessel.
b. a vessel equipped with hydrofoils.
[ 1915-20; HYDRO- 1 + FOIL 2 ]