Roof box is a useful tool for any traveler who wants to carry extra luggage on top of their vehicle while on a road trip. However, it's not the only term used for this accessory. Other synonyms for roof box include cargo box, roof cargo carrier, roof rack box, roof storage container, and rooftop cargo box. A cargo box is a general term to refer to storage space attached to the roof of a vehicle, whereas a roof cargo carrier emphasizes its function of holding additional items. Roof rack box and rooftop cargo box are more specific terms that describe the shape and location of the storage container, while roof storage container is a comprehensive term for any storage device installed on the vehicle's roof.