in a 4 line inflatable kite is a the line that goes from the loop at the center of the control bar (chicken loop) to the two flying lines connected to the front of the kite. Adjusting its length adjusts the "trim" or angle of attack (AoA) of the kite. Changing this adjustment can increase the AoA for more lift or decreasing the AoA for less lift.

an assembly line where various parts are assembled into a car body

Line on artwork indicating where to cut to remove the waste on a printed piece.

Line on artwork used where to the waste on a printed paper.

(kite surfing) a line that adjusts the angle of attack (primarily used for inflatable 4 line kites) which runs from the wingtips to the control bar centre or through a hole in the control bar attaching to the harness.