What is a "cookie sheet"?

A cookie sheet, also known as a baking sheet or baking tray, is a flat, rectangular metal pan used for baking cookies, pastries, and other baked goods in the oven. It typically has a shallow rim around the edges to contain food items and prevent spills or drips. Cookie sheets come in various sizes and materials, including aluminum, stainless steel, or non-stick coatings, each offering different advantages for baking and cooking.