bar cookie [bahr kook-ee] noun
A soft-baked good baked in a square or rectangular pan (typically cut into squares or rectangles after baking). Brownies and blondies are the most common bar cookies, and when you spread classic chocolate chip cookie dough into such a pan and bake, it becomes a bar cookie as well. Classic lemon bars are included in this category and are a good example of how sometimes the word “cookie” is left out of the name. They are cookies in the sense that they are still small, individual treats.