Definition
A solid white line painted down the middle of a runway along its full length, broken into uniform stripes with regular gaps. Centerline markings provide a visual reference for keeping the aircraft aligned with the runway during takeoff and landing.
Plain English
The dashed white line painted down the centre of a runway. You use it to keep the aircraft straight along the middle of the runway as you take off or land.
Context Anchor
Seen on the runway surface during taxi, takeoff, landing, and runway lineup.
Derivation
Center combines the idea of a middle point with line as a continuous mark; in aviation the term specifically denotes the precise middle alignment path of the runway surface.
Why Pilots Care
Proper alignment with centerline markings keeps the aircraft on the prepared runway surface and is especially critical in crosswinds or low visibility.
Intuition Check
Do not think of centerline markings as decoration or just paint on pavement. In this context, they are a visual guide for keeping the aircraft aligned with the middle of the runway.
Example Sentence 1
After touchdown, she eased in right rudder to track the centerline markings as the crosswind pushed the nose left.
Example Sentence 2
After landing in a crosswind, the pilot used the centerline markings to maintain directional control.