fortress, noun, /'fɔrtrəs/
a large strong building used for defending an important place.
a building or place that has been made stronger and protected against attack.
a fortress town enclosed by four miles of ramparts.
Fear of terrorist attack has turned the conference centre into a fortress.
monolith, noun, /'mɑnə'lɪθ/
1
a large powerful organization that cannot change quickly and does not consider the ideas or feelings of the people it affects.
a very large and powerful organization that acts as a single unit.
It is misleading to see the legal system as a monolith.
The media monolith owns a number of networks.
a global monolith.
2
a large tall block of stone, especially one that was put in place in ancient times, possibly for religious reasons.
a very large stone that is usually tall and narrow.
a stone that was put in position by people as a monument or for religious reasons.
a very large building or other structure.
an ancient monolith.
The new office building is a massive steel and concrete monolith.
monolithic, adjective, /ˌmɑnə'lɪθɪk/
a large, monolithic building. a monolithic organization.
monolithic, adjective, /ˌmɑnə'lɪθɪk/
1
a monolithic building is very large, solid, and impressive.
2
a monolithic organization, political system etc is very large and powerful and difficult to change.
too large, too regular or without interesting differences, and unwilling or unable to be changed.
a monolithic movie company.
monolithic state-run organizations.
a monolithic nationalized industry.
a monolithic fortress.