The term refers to an automotive body style characterized by three distinct volumes: the engine compartment, the passenger area, and the cargo area. Each section is clearly defined and visually separate. A typical example is a sedan, where the hood (engine), cabin (passengers), and trunk (cargo) are readily identifiable as individual boxes.
This design offers advantages such as increased structural rigidity, improved sound insulation between the engine and passenger compartments, and a dedicated, enclosed space for luggage or goods. Historically, it became a prevalent configuration due to its practicality and perceived elegance, dominating the automotive landscape for much of the 20th century. Its clear separation of functions contributed to passenger comfort and efficient use of space.
