Plain English Meaning

Going sideways along the wing, from where it joins the body of the airplane out to the tip — the long direction of the wing.

Full Definition

Along the direction of the wingspan — that is, from the wing root (where the wing meets the fuselage) outward toward the wingtip, or from one wingtip across to the other. Used to describe airflow, pressure distribution, structural members, or any movement or measurement that runs across the wing from side to side rather than front to back.

Context Anchor

Seen in aerodynamic discussions of airflow over the wing, especially when explaining induced drag and .