A hardtop is a rigid form of automobile roof, typically metal, and integral to the vehicle's design, strength, and style. The term typically applies to a pillarless hardtop, a car body style without a B-pillar. The term "pillared hardtop" was used in the 1970s to refer to cars that had a B-pillar but had frameless door glass like a pillarless hardtop.
In limited cases, a hardtop roof can be detachable (often designed to store in the trunk), or retractable within the vehicle itself.