What does viscosity refer to in a liquid?

Viscosity refers to the thickness or thinness of a liquid, indicating how resistant it is to flow. A high viscosity means the liquid is thick and flows slowly, like honey or molasses, while a low viscosity indicates the liquid is thin and flows easily, such as water or alcohol. In the context of cosmetology, understanding viscosity is important when working with hair products, as it can affect application methods and the overall performance of products like shampoos, conditioners, and styling gels. Products with varying viscosities can behave differently during use, affecting their ease of application and effectiveness on the hair.