Refers to a person or thing that serves as a central support or foundation, often in an organization or society. Can be used literally for a structural pillar, but the figurative sense is more common.
He has worked for many years as a pillar of the company.
Education is the cornerstone of a nation.
andalusite
beryl
pillar of state; mainstay of the nation
Compound of 柱 (pillar) and 石 (stone). The combination suggests a stone pillar or a pillar-like stone, metaphorically extended to mean a foundational support.