What body type tells you, and what it does not

Body type describes a vehicle's outer shape and how its interior volume is divided. The difference between a sedan and a hatchback is whether the luggage volume is designed as a compartment separate from the passenger cabin. Put BMW 320i and Volkswagen Golf side by side and the distinction becomes visible.

The list of things this label does not tell you is longer than the list of things it does. Body type says nothing about how fast a vehicle is, what drives it, how many people it carries or what it costs. Two vehicles carrying the same body label may have been designed for completely different work.

In the air the same word does a different job. A "narrow-body" airliner is named after the aisle arrangement inside the cabin, which does not follow the same logic as body labels on the land side. Airbus A320neo carries that label, and the label only resolves within an aviation context.

At sea, body type is usually entangled with the means of propulsion. The difference between a sailing yacht and a motor yacht is both formal and functional; Bénéteau Oceanis 46.1 and Azimut Grande 27M share a main category and almost no design assumptions.

That is why body type is used here as a narrowing axis rather than a classifying one. If you are looking for a shape, it is the right tool; if you are looking for a purpose, the category tree gives the better answer. How the two work together is covered in How to read this catalogue.