noun, plural: viscosities

(1) The state or condition of being viscous

(2) The physical property of a fluid that determines the internal resistance of a fluid to flow


Viscosity is the state or condition of being viscous. It is measured as a physical property of a fluid. A fluid's viscosity is measured by determining its internal resistance to gradual deformation by shear forces or tensile stress.1 Pitch, which is a dark viscous waxy material derived from tar, may be the most viscous fluid and is an average 100 billion times as viscous as water.1

The viscosity of a fluid is influenced by the following factors: molecular structure, external forces, and ambient conditions. The molecular structure of a fluid influences viscosity in a way that when the molecules are tightly linked, the higher is the resistance to deformation, and therefore it will have less tendency to flow. External forces such as shear forces or tensile stress act upon the fluid and therefore influence the flow of the fluid. The ambient conditions also affect viscosity. For instance, the viscosity of a fluid is lower when the temperature is higher. Therefore, a decreasing ambient temperature will increase the viscosity of a fluid.2

Word origin: Latin viscositas, from Latin viscosus

See also:

Related term(s):

Mentioned in:

1 Hammonds, M. (2013). The World’s Slowest Experiment. Retrieved from
2 Factors Affecting Viscosity. (n.d.) Retrieved from

Retrieved from ""
First | Previous (Viscoelasticity) | Next (Viscous) | Last
Please contribute to this project, if you have more information about this term feel free to edit this page.