The wall behind a countertop is commonly referred to as a backsplash. The purpose of a backsplash is to protect the wall from splashes, stains, and moisture that can occur during activities such as cooking or washing dishes. It is often made of materials such as tiles, glass, stainless steel, or even a painted surface. The backsplash also serves as a design element, adding visual interest and complementing the overall aesthetic of the kitchen or bathroom.