Young-Laplace equation

Etymology
Named after Thomas Young, who developed the qualitative theory of surface tension in 1805, and Pierre-Simon Laplace, who completed the mathematical description in the following year.

Proper noun

 * 1)  A nonlinear partial differential equation that describes the capillary pressure difference sustained across the interface between two static fluids, such as water and air, due to the phenomenon of surface tension or wall tension.