Battlesight Zero
Also: Battle Zero
A single practical zero chosen so that aiming corrections stay small across the most common engagement distances.
A battlesight zero is one fixed zero selected so the bullet’s path never strays far from the line of sight across a band of likely shooting distances, letting the shooter aim center and fire without dialing. Military rifles adopted the idea so a soldier could engage targets from close range out to a few hundred meters with the same sight setting and only minor holds. The chosen distance is a compromise that keeps the rise and the drop both inside an acceptable margin.
The logic is closely related to point blank range thinking, trading pinpoint precision at any one distance for speed and simplicity across many. It is the natural zero for fixed iron sights or any rifle where dialing a turret is impractical under time pressure. Pushed to its limit, the same reasoning produces a maximum point blank range for a defined target size.