1. The offices of a commander, as of a military unit, from which orders are issued.
2. A center of operations or administration:
3. The noun headquarters is used with either a singular or a plural verb. The plural is more common:
名词headquarters 可以和单数或复数动词连用。 复数更为常用：
The headquarters are in Boston.
4. But the singular is sometimes preferred when reference is to authority rather than to physical location:
Battalion headquarters has approved the retreat.