Shear-thinning is a property of certain fluids where their viscosity decreases when subjected to shear stress or agitation. This means that when you stir or shake a shear-thinning fluid, it becomes easier to flow. Common examples include paint, ketchup, and blood, which all become less thick when mixed or pumped. This behavior is important in various applications, such as in the food industry and in medical treatments. For instance, ketchup flows more easily when shaken, making it easier to pour. In medical contexts, shear-thinning properties can help blood flow more efficiently through blood vessels.