Poiseuille's law

noun

Poi·​seuille's law pwä-ˈzə(r)z-, -ˈzwēz-, -ˈzə-ēz- 

: a statement in physics: the velocity of the steady flow of a fluid through a narrow tube (as a blood vessel or a catheter) varies directly as the pressure and the fourth power of the radius of the tube and inversely as the length of the tube and the coefficient of viscosity