say it: HED-kwawr-turz
headquarters is a noun meaning "(usually plural) the office that serves as the administrative center of an enterprise". It carries 3 recorded senses.
(usually plural) the office that serves as the administrative center of an enterprise
“many companies have their headquarters in New York”
plural
the military installation from which a commander performs the functions of command
“the general's headquarters were a couple of large tents”
plural · military
(plural) a military unit consisting of a commander and the headquarters staff
plural · military
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for headquarters come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.