A dilatant is a type of non-Newtonian fluid that becomes thicker and more viscous when subjected to stress or shear. This means that when you apply force, such as stirring or squeezing, the fluid resists flow and can even become solid-like. Common examples of dilatant materials include certain types of cornstarch mixed with water, often referred to as oobleck. Dilatant behavior is the opposite of pseudoplastic fluids, which become thinner when stress is applied. Understanding dilatant properties is important in various fields, including materials science and engineering, as it helps in designing products that require specific flow characteristics under different conditions.