retractable roof
All or part of the roof can be moved back and forth to expose or cover the interior.
A retractable roof is an upper shell of a building which is capable of being moved easily, in whole or in part, in order to expose at least a section of the interior to the outdoors. Usually a retractable roof slides open on tracks, but it can also be folded open, lifted like a lid by a permanent arm, or opened like a fan or an iris. Retractable roofs are virtually essential to convertible stadiums, but can also be found on other structural forms. This feature does not apply to openable skylights or trap doors in a roof; it must involve a major section of the roof.
The moving part is a major section of the roof shell. Sliding is one possible mechanism; folding, lifting, and other opening motions also fall within the definition.
An openable skylight or small roof access hatch is insufficient. A partly open roof describes an opening in the overhead coverage without requiring the movement that defines a retractable roof.