Bunker

A bunker was a type of defensive structure, intended to protect their content from attack.

On Earth, bunkers were used as early as the Second World War. In a holographic simulation, American forces attacked a German bunker. 

The Borg Cooperative was centered in a bunker. 

The Siege of AR-558 revolved around the protection of a communications bunker in the Chin'toka system. Also during that war, the Tevak shipyards had its dilithium storage bunkers destroyed.