(usually plural) the office that serves as the administrative center of an enterprise
"many companies have their headquarters in New York"
the military installation from which a commander performs the functions of command
"the general's headquarters were a couple of large tents"
(plural) a military unit consisting of a commander and the headquarters staff
"The general ordered his entire force to retreat to its new headquarters before nightfall."
The military installation from which troops are commanded and orders are issued; the military unit consisting of a commander and his support staff.
"The general ordered all units to regroup at headquarters immediately after receiving the new directive."
In plain English: Headquarters is the main office where a company or organization is based and runs its operations.
"The company moved its headquarters to a new building downtown."
Usage: Use headquarters to refer to the main office or base where an organization's leadership operates and directs activities. While it originated in a military context, it now commonly describes the central location for any large group, such as a corporation or non-profit.
The word headquarters is a compound formed from "head," meaning chief or leader, and "quarters," referring to living space or lodging. It originally described the primary residence of a military commander before evolving into its modern sense for any central office or base of operations.