What is the difference between a wing station and wing buttock line?
The wing stations are perpendicular to the leading edge. Wing station zero is typically where the leading edge meets the fuselage. Wing ribs are typically parallel to the wing station. On swept wing aircraft, this won't match the flow direction, but it makes design and construction easier.

The wing buttlines are parallel to the airplane buttlines, which run down the length of the aircraft. Wing buttline zero is typically where the wing meets the fuselage.

This means that, unlike with other sections like the fuselage, the wing stations and buttlines are not perpendicular if the wing has sweep.



Rough illustration of the wing vs. fuselage BL and STA. Not to scale.