Plain English Meaning
How much weight the wings have to carry, spread across their area. A higher number means each part of the wing is working harder to keep the airplane up.
Full Definition
The aircraft's gross weight divided by the total wing area, usually expressed in pounds per square foot. It indicates how much weight each square foot of wing must support in flight.
Context Anchor
Encountered in discussions of landing performance, approach speed, stall speed, and how an airplane feels during the approach and touchdown.
Derivation
Loading comes from , meaning the weight or burden being carried. In , wing loading means the load carried by the wings, spread across the wing area.