Definition

Noun: - Resistance to flow: The physical property of a fluid (liquid or gas) that describes its internal resistance to flow and shear forces. A high viscosity means the fluid is thick and flows slowly (like honey), while a low viscosity means the fluid is thin and flows easily (like water).

Examples of Usage

• Noun:
  • The viscosity of the oil is critical for proper engine lubrication.
  • Honey has a much higher viscosity than water.
  • Scientists measure the viscosity of lava to predict its flow during a volcanic eruption.

Advanced Usage

• Dynamic (or Absolute) Viscosity: A measure of a fluid's resistance to shear flow when an external force is applied. It is often represented by the Greek letter eta (η).
  • The experiment calculated the dynamic viscosity of the polymer solution.
• Kinematic Viscosity: The ratio of dynamic viscosity to fluid density. It is often represented by the Greek letter nu (ν).
  • Kinematic viscosity is important for understanding how fluids behave under gravity.

Variants and Related Words

• Viscous (adjective): Having a thick, sticky consistency between solid and liquid; having high viscosity.
  • The crude oil was cold and viscous.
• Viscousness (noun): A synonym for viscosity.
  • The viscousness of the syrup made it pour slowly.

Synonyms

• Thickness: (Informal) The quality of being thick or semi-fluid.
• Consistency: The degree of viscosity or firmness of a substance.
• Gumminess: The quality of being sticky and thick.
• Glutinousness: The quality of having a glue-like, sticky nature.

Related Phrases and Collocations

• High/Low viscosity: Describes the degree of a fluid's resistance to flow.
  • Motor oils are graded based on their high and low temperature viscosity.
• Viscosity index: A measure of how much the viscosity of an oil changes with temperature.
  • A high viscosity index is desirable for engine oils.
• Shear viscosity: Another term for dynamic viscosity, emphasizing resistance to shear stress.
  • The shear viscosity decreases as the fluid is stirred more vigorously.

Noun

1. resistance of a liquid to shear forces (and hence to flow)