A barbecue grill is a device that cooks food by applying heat from below. There are several varieties of grills, with most falling into one of two categories charcoal. There is debate over which method yields superior results A barbecue grill is a device that cooks food by applying heat from below. e that cooks food by applying heat from below. There are several varieties of grills, with most falling into one of two categories charcoal. There is debate over which method yields superior results A barbecue grill is a device that cooks food by applying heat.