Sight Alignment
The act of lining up the front and rear sights correctly with each other, which is the core skill behind accurate iron-sight shooting.
Sight alignment is the geometric relationship between the rear sight and the front sight, held correctly before the target ever enters the equation. With open iron sights that means centering the front post in the rear notch with equal light on each side and the tops level. With an aperture sight the eye naturally centers the front post in the rear ring, which is part of why peep sights are so precise.
Alignment matters more than where the sights point, because a small angular error between front and rear multiplies enormously by the time the bullet reaches a distant target. Once the sights are aligned, the shooter brings that aligned unit onto the target to form the full sight picture. Holding that alignment depends on a sharp front sight focus, since the eye can only truly focus on one plane at a time.