Viscosity is a fundamental property of fluids that describes their resistance to flow. It is a measure of the internal friction within the fluid, with higher viscosity fluids being thicker and more resistant to flow, while lower viscosity fluids are thinner and flow more easily. Viscosity plays a crucial role in various scientific and engineering disciplines, such as fluid dynamics, materials science, and chemical engineering. Researchers study the viscosity of fluids to understand their behavior, predict their flow characteristics, and optimize their performance in various applications.