In the Halo franchise, what is the name of the human military organization abbreviated as UNSC?

In the Halo franchise, UNSC stands for United Nations Space Command.

The United Nations Space Command is the principal human military, governmental, and colonial authority in the series. It operates fleets, armies, intelligence services, research programs, and colonies across human-controlled space. Master Chief and many other human characters serve within its military structure.

The UNSC’s major branches include the Navy, the Army, the Marine Corps, and the special operations organization known as the Office of Naval Intelligence. The Spartan programs are also developed under UNSC authority, particularly through military and scientific institutions.

UNSC is sometimes misread as a name for only the navy or only the military. In the fiction, it is a broad human command structure, while the UNSC Navy is one specific branch. The organization’s long war with the Covenant forms the political and military background of the original games.