A baking dish is a typically wide, shallow, rectangular cooking vessel, usually for placement into an oven for baking or roasting. A popular size is 9 inches by 13 inches, especially for dishes like lasagna or brownies.
Baking dishes can be made of borosilicate glass (i.e. Pyrex), stoneware, ceramics or metal. Same may come with a nonstick coating. Not all baking dishes are microwave safe, so be sure to check the label on the dish before using in the microwave.
Baking dish

A glass baking dish.