A US military reservation in Kentucky, famous as the site of the depository (built in 1936) which holds the bulk of the nation's gold bullion in its vaults.
Definition of Fort Knox in US English:
Fort Knox
proper nounˌfɔrt ˈnɑksˌfôrt ˈnäks
A US military reservation in Kentucky, noted as the site of the depository, which was built in 1936, that holds the bulk of the nation's gold bullion in its vaults.