Definition of "hydrodynamics" [hy•dro•dy•nam•ics]

• The branch of science that deals with the dynamics of fluids, especially incompressible fluids, in motion. (noun)
• The dynamics of fluids in motion. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Furthermore, magneto-hydrodynamics is important in discussing the problem of how the central body in a plasma cloud can develop into a sun and system of planets, or in investigations of stability conditions for a plasma consisting of electrons and ions moving at relativistic velocities interacting with cosmic fields."
• "Prof. Walton's first researches involved theoretical and experimental studies in hydrodynamics and, at the Cavendish"
• "Liquid crystals have been known for over a century and their hydrodynamics, that is, how they flow, were studied as early as the 1920s by Professor Wilhelm Oseen of Uppsala."