Plain English Meaning
Knowing the right moment to start leveling the wings so the airplane is straight and level exactly when it crosses the line on the ground.
Full Definition
The judgment of when to begin reducing bank angle so that the airplane arrives wings-level precisely as it crosses the reference line during an S-turn or similar ground reference maneuver. Rollout timing must account for the rate of turn, the current bank angle, groundspeed, and any wind effect that is pushing the airplane toward or away from the reference line.
Context Anchor
Used during and other , especially when judging when to stop turning near a road or other selected line on the ground.