Definitions for "Racing line"
The imaginary line on which the racing circuit can be driven in the fastest possible time. This is also usually where the grip is best.
An imaginary line around a circuit that has been proven to be the most efficient and quickest route around the circuit.
The optimal path around a race track that results in the fastest possible lap. May vary between cars of radically different natures, such as a heavy GT car and a light formula car.
The ideal route along the course, explained at length before the week's racing by the coach and promptly forgotten by coxes who prefer to choose their own crossover point on the Greenbank.