A grille is a perforated cover for an air duct (used for heating, cooling, or ventilation, or a combination thereof). Grilles sometimes have louvers which allow the flow of air to be directed. A register differs from a grille in that a damper is included.[1][2] However, in practice, the terms grille, register, and return are often used interchangeably, and care must be taken to determine the meaning of the term used.
Grill
