Tool: Cookie Sheet
A flat, rectangular, metal pan used for baking foods such as cookies. A true cookie sheet has no sides, making it easier to transfer baked goods to a cooling rack. A baking sheet has 1/2-inch high sides and can be used in a wide variety of ways. Extremely versatile, this is one of the most valuable tools in the kitchen.
Often called a "half-sheet" pan, it is about 11x17-inches. A full-sheet pan is used in professional kitchens and is twice the size of a normal baking sheet.