The headquarters of an organisation is the main office it is run from. Company headquarters, police headquarters, move the headquarters to Leeds.
The word looks plural and takes either a singular or a plural verb — headquarters is in Geneva and headquarters are in Geneva are both used, with the singular commoner. There is no singular form headquarter as a noun. HQ is the abbreviation and head office the British business equivalent. As a verb, be headquartered in is standard: the company is headquartered in Dublin. The military sense — a command post — is the original one.
1nounheadquartersThe main office an organisation is run from.
“The headquarters moved out of London in the nineties.”
synonyms: head office, HQ
headquarters is a main office.
Also accepted in games: hq, head office
From head + quarter.
Etymology from Wiktionary, CC BY-SA