framework of a building; foundation
Literally the structural framework or skeleton of a building, especially the main supporting beams. Often used metaphorically.
The framework of the old house has rotted.
The building's framework shook violently in the earthquake.
mainstay; backbone; supporting pillar
Figurative use for the central supporting element of an organization, family, or system. Can refer to a person who is the main breadwinner or key figure.
He is the mainstay that supports the company.
After my father passed away, the family's foundation became shaky.