\Hy*drau"lics\, n. [Cf. F. hydraulique.]
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.

Note: As a science, hydraulics includes hydrodynamics, or the
      principles of mechanics applicable to the motion of
      water; as a branch of engineering, it consists in the
      practical application of the mechanics of fluids to the
      control and management of water with reference to the
      wants of man, including canals, waterworks, hydraulic
      machines, pumps, water wheels, etc. Some writers treat
      hydraulics and hydrostatics as subdivisions of
      hydrodynamics.