cornerstone
- (noun): A stone forming the base at the corner of a building.
- (noun): Such a stone used ceremonially, often inscribed with the architect's and owner's names, dates and other details.
- (noun): That which is prominent, fundamental, noteworthy, or central.
- The cornerstone on the Flatiron Building is set on the Fifth Avenue facade.
- Exceptional service is the cornerstone of the hospitality industry.