"Structure." A lot of architectural terms have multiple meanings. "Structure" is one. While it can refer to the components (beams, joists, columns, rafters, footings) that hold up a building, it can also refer to the way a space is organized.
Certainly this comes from when a building's structure was fundamentally tied to spatial organization. But new technologies and materials have made it possible to completely separate space and structure from each other, as architects like Mies van der Rohe did.