When a fluid quickly flows out of its container. Viscosity is a measure of resistance. The resistance in this measurement is associated with how fluids flow. It is how thick a liquid is. Viscosity is also related to how dense fluid is. Pascal-seconds is used to measure viscosity.
The abbreviation for Pascal-seconds is Pas. Along with fluids, gases are also related and can have viscosity. Water would be an example of a fluid with a low viscosity. To compare, honey has a high viscosity because it is much thicker than fluids with a low viscosity.