A roof cavity deliberately designed to let in light, covered with a translucent material.

This includes glass atriums, domes and many large areas of glass panelling in commercial buildings, as well as residential skylights.

It includes a permanent greenhouse that is purely made of translucent glass or hard plastic.

Glass on walls, even if visible due to building lean (in e.g. skyscrapers and greenhouses).

Flexible, temporary plastic fabric over plants that provides some protection and creates a greenhouse effect, but isn't a permanent waterproof structure.

• US
• Australia