In automotive engineering, a grille covers an opening in the body of a vehicle to allow air to enter or exit. Most vehicles feature a grille at the front of the vehicle to protect the radiator and engine. Merriam-Webster describes grilles as "a grating forming a barrier or screen; especially: an ornamental one at the front end of an automobile." The word 'grille' is commonly misspelled as 'grill' which instead refers to the cooking method. Other common grille locations include below the front bumper, in front of the wheels (to cool the brakes), in the cowl for cabin ventilation, or on the rear deck lid (in rear engine vehicles). Grilles evolved from previously installed gravel shields that were designed to protect exposed radiators typically used on cars until the early 1930s.