An imaginary line drawn down the center of an object (like the centerline of a plumbing fixture). Most commonly used to dimension the distance from the center of a fixture to a fixed or stationary point – like a wall or the centerline of a structural column (column grid).
For example, NCIDQ Building Code 5.8.2: Centerline of accessible toilets MUST be 16”-18” [400 mm – 450 mm] from side wall or partition.
Not to be confused with on center.