A cooker is a large appliance used for preparing food, especially by heating or baking. In British English, what Americans call a “stove” or “range” is called a cooker: the big kitchen appliance with burners on top and an oven below. A family might roast a chicken in the cooker's oven while boiling pasta on the cooker's burners.

The word can also refer to specific types of cooking devices. A pressure cooker uses steam pressure to cook food quickly. A slow cooker gently heats food over many hours, perfect for making stew or chili while you're at school. A rice cooker is designed specifically for cooking rice perfectly every time.

Sometimes people use “cooker” more generally to mean any device used for cooking, though this is less common than the British usage for a full kitchen range. The plural cookers always refers to the appliances themselves, not the people doing the cooking: those are cooks or chefs.