1 : installation from which a military force initiates operations
2 : a stronghold that is reinforced for protection from enemy fire; with apertures for defensive fire
3 : the place where you are stationed and from which missions start and end
4 : a terrorist network intensely opposed to the United States that dispenses money and logistical support and training to a wide variety of radical Islamic terrorist groups; has cells in more than 50 countries
5 : (usually plural) the office that serves as the administrative center of an enterprise
