\Hy`dro*dy*nam"ics\, n. [Hydro-, 1 + dynamics: cf.
F. hydrodynamique.]
That branch of the science of mechanics which relates to
fluids, or, as usually limited, which treats of the laws of
motion and action of nonelastic fluids, whether as
investigated mathematically, or by observation and
experiment; the principles of dynamics, as applied to water
and other fluids.

Note: The word is sometimes used as a general term, including
      both hydrostatics and hydraulics, together with
      pneumatics and acoustics. See {Hydraulics}.