- The definition of unibody is a type of motor vehicle construction where a single entity or a single molded unit forms a car's body work and chassis.
The molded frame of a hot rod is an example of a unibody construction.
unibody definition by Webster's New World
designating or of a type of construction used in motor vehicles in which the floor, roof, panels, etc. are welded together into one unit, thereby eliminating the need for a separate frame