Wiktionary
n. (context architecture English) An architectural design in which a room has a large hole in its ceiling, open to the sky.
Wikipedia
A skyspace is an architectural design in which a room, which is painted in a neutral color has a large hole in its ceiling which opens directly to the sky. The room, whose perimeter has benches, allows observers to look at the sky in such a way as though it were framed. LED lights which surround the hole can change colors to affect the viewer's perception of the sky.
The design is the work of American artist James Turrell. As of 2013 over 82 skypaces have been installed worldwide. Examples include the Skyspace at Live Oak Friends Meeting in Houston, Texas and at Rice University, also in Houston.