A long, gentle curve.
The long "sweeping" turn that leads from the staging lanes, past the tower, and out onto the quarter mile straightaway. One of the most challenging sections of the track, to master the sweeper is to induce drift while still in the staging lanes, maintain a constant radius drift through the entire sweeper and end on the straightaway at high speed. The guardrails on both sides of the sweeper and narrow roadway make this corner particularly dangerous.
A flat curve on a track
( noun) A long large curve that is typically a large radius. See decreasing radius turn and twisties.
A wide turn.
A large banked turn is called a bank, a large flat turn is called a sweeper.