main body (of troops); main force
Refers to the principal unit or core group of a military or organized force, often contrasted with detached units (支隊).
See also: 支隊
The main force departed before dawn.
支隊が本隊と合流した。
The detachment rejoined the main body.
this troop; these troops
Used within a military context to refer to one's own unit or the troops currently being discussed; not a general demonstrative.
本隊はただちに現地へ向かう。
This unit will head to the site immediately.
The reconnaissance unit rejoined the main force three days later.
Some soldiers broke away from the main force and acted independently.
The general personally led the main force forward.