What does the word hydraulic?
1. operated by, moved by, or employing water or other liquids in motion. 2. operated by the pressure created by forcing water, oil, or another liquid through a comparatively narrow pipe or orifice. 3. of or pertaining to water or other liquids in motion. 4. of or pertaining to hydraulics. 5. hardening under water, as a cement. (i just looked it up)