(also kinematic modulus of viscosity), the ratio of the conventional modulus of viscosity η (also called the dynamic coefficient) to the density of the substance ρ; it is designated by ν. In the International System of Units the unit of kinematic viscosity is m²/sec. A fractional unit of kinematic viscosity, cm²/sec, is called the stokes: 1 m²/sec = 10⁴ stokes.