What's the difference between a cookie sheet and a baking sheet?

A cookie sheet (also called a baking sheet) is flat with minimal or no raised edges, making it easy to slide cookies off. A sheet pan (also called a baking pan or jelly roll pan) has raised rims on all four sides, containing liquids and preventing items from sliding off. For cookies specifically, either works well, but the rimless cookie sheet makes it slightly easier to transfer cookies to a cooling rack.