dynamic viscosity

The dimensions of dynamic viscosity are force × time ÷ area. The unit of viscosity, accordingly, is newton-second per square metre, which is usually expressed as pascal-second in SI units.

This constant is called the dynamic, or absolute, viscosity and often simply the viscosity. Fluids that behave in this way are called Newtonian fluids in honour of Sir Isaac Newton, who first formulated this mathematical description of viscosity.