What does the term “unibody” refer to?

The term "unibody" refers specifically to a vehicle design where the body and chassis are a single unit. This design approach integrates the car's body structure and its chassis into one cohesive component, which can improve rigidity and reduce weight compared to traditional body-on-frame vehicles where these components are separate.

Unibody designs are popular in modern vehicles because they contribute to better crash safety, enhanced handling, and improved fuel efficiency. This construction method allows for more efficient use of materials and creates a streamlined design that can also assist in aerodynamics. In contrast, the other options describe different concepts that do not accurately define “unibody.” For instance, the separation of body and chassis is typical in older vehicle designs rather than in unibody vehicles, which clearly identifies the distinction between vehicle construction methodologies.