D defs.my
Entry 1 sense Webster, 1913

Hydraulics

/hīd-rôl'-ĭks/ · Hy·drau·lics · IPA /haɪˈdɹɔːlɪks/
01 n. That branch of science, or of engineering, which treats of fluids in motion, especially of water, its action in rivers and canals, the work…
  1. 1.
    That branch of science, or of engineering, which treats of fluids in motion, especially of water, its action in rivers and canals, the works and machinery for conducting or raising it, its use as a prime mover, and the like.