noun, plural head·quar·ters. ( used with a singular or plural verb )
1.
a center of operations, as of the police or a business, from which orders are issued; the chief administrative office of an organization: The operatives were always in touch with headquarters.
2.
the offices or working location of a military commander; the place from which a commander customarily issues orders.
3.
a military unit consisting of the commander, his staff, and other assistants.