Noun
a cooking utensil consisting of a flat rectangular metal sheet used for baking cookies or biscuits
Source: WordNetWhen people tell me they are going to go scrapbooking, I say, 'Why don't you make it yourself.' It's like chocolate-chip cookies. People buy the cookie-dough roll and slice it, and then they lay it on a cookie sheet. That's not making chocolate-chip cookies. Amy Sedaris