 The practical use of distributions can be traced back to the use of Green functions in the 1830s to solve
ordinary differential equations, but was not formalized until much later.According to , generalized functions originated in the work of on second-order hyperbolic partial differential equations, and the ideas were developed in somewhat extended form by Laurent Schwartz in the late 1940s.According to his autobiography, Schwartz introduced the term "distribution" by analogy with a distribution of electrical charge, possibly including not only point charges but also dipoles and so on.