Viscosity means how thick or thin a fluid is and how easily it can flow. Viscosity tells us how much a fluid resists moving. You can think of it as the internal friction inside a liquid. • Water flows fast → low viscosity • Honey or gear oil flows slow → high viscosity Engineers use viscosity to choose the right oil for machines, design pipelines, select pumps, and understand how fluids behave during flow. Example If you pour water, it runs quickly. If you pour honey, it moves slowly. This difference happens because honey has higher viscosity than water. Viscosity is the internal friction of a fluid that resists flow. | Process Design Engineering | | Best Process Engineering Institute in India |