Sunblock is a type of skincare product designed to protect the skin from harmful ultraviolet (UV) rays emitted by the sun. It works by forming a physical barrier on the skin that reflects or scatters UV radiation, preventing it from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Sunblock typically contains ingredients like titanium dioxide or zinc oxide, which provide broad-spectrum protection against both UVA and UVB rays.