After all, aerodynamics and electrodynamics are just theories, too.
Equations with several dependent variables occur in Elasticity, electrodynamics, and Hydrodynamics.
The history of electrodynamics is particularly instructive from our point of view.
It is a question before all of endeavoring to obtain a more satisfactory theory of the electrodynamics of bodies in motion.
Principles of electrodynamics, motion produced by an electric current—Ampère, France.
The scientific study of electric charge and electric and magnetic fields, along with the forces and motions those fields induce. See also electromagnetism.