A back splash prevents spilled liquids food and other materials from falling behind the cabinets. A back splash is often used as an upperward extension to the back of the countertop. Howerver, the area on the wall above the back of the countertop is also often reffered to as a back splash.  Another area can be be above the stove. These areas are usually decorated with tile and or other materials that are usually easy to clean and maintain.