hydraulics

n [sing or pl v] science of using water to produce power 水力学.

hustings, hustle, hustler, hut, hutch, hutment, hutted, hyacinth, hyaena, hybrid, hybridize, hybridise, Hyde Park, hydr(o)-, hydra, hydrangea, hydrant, hydrate, hydration, hydraulic, hydraulically, hydrocarbon, hydrochloric, hydroelectric, hydroelectrically, hydroelectricity, hydrofoil, hydrogen, hydrogen bomb (also H-bomb), hydrogen peroxide, hydrometer, hydrophobia, hydroplane, hydroponics, hydrotherapy, hyena (also hyaena), hygiene, hygienic, hygienically, hymen, hymn,