hydroplane

n 1 light motor boat with a flat bottom, that can travel fast over the surface of the water 机动平底快艇. 2 device on a submarine enabling it to rise or descend （控制潜艇升降的）水平舵.

hydr(o)-, hydra, hydrangea, hydrant, hydrate, hydration, hydraulic, hydraulically, hydraulics, hydrocarbon, hydrochloric, hydroelectric, hydroelectrically, hydroelectricity, hydrofoil, hydrogen, hydrogen bomb (also H-bomb), hydrogen peroxide, hydrometer, hydrophobia, hydroponics, hydrotherapy, hyena (also hyaena), hygiene, hygienic, hygienically, hymen, hymn, hymnal, hyp-, hypo-, hype, hyper-, hyperactive, hyperactivity, hyperbola, hyperbole, hyperbolic, hyperbolical, hypercritical, hypercritically,