it is the width of the wing:
when you enter the aerofoil chord, its maximum thickness and camber are updated immediately
maximum thickness / chord = relative thickness
camber or arrow = maximum distance between the rope and the center line profile
- The lift but also drag,of a profile increases with its camber and thickness
- The thin profile and low camber, have a better lift / drag ratio but less strength...
for more information: the chord of aerodynamic and hydrodynamic profiles