From an online encylopedia
A convertible is a type of automobile in which the vehicle's roof can retract and fold away, converting it from an enclosed to an open-air vehicle. Many different automobile body styles are manufactured and marketed in convertible form.

Roof designs vary widely, but a few characteristics are common to all convertibles. Roofs are affixed to the body of the vehicle and are usually not detachable. Instead the roof is hinged and folds away, either into a recess behind the rear seats or into the boot of the vehicle. The roof may be designed to operate either by hand or automatically using hydraulic or electrical actuators.

Roofs can be made out of a wide variety of materials, and are usually divided in two types: soft-tops and hard-tops. Soft-tops are made of vinyl, canvas or other textile material, while hard-tops are usually made of the same material as the car's body (usually steel or aluminium).

Convertibles are known by different terms, mainly due to convergence of various body styles and also different marketing terms used. A soft-top convertible may also be referred to as a cabriolet, although two-seater soft tops retain the name roadster, referring to their body style. Hard-tops are marketed under the terms coupé cabriolet, coupé convertible or simply retractable hardtop.