Definition
The outer covering of an aircraft wing (or fuselage) that forms its aerodynamic surface. On most modern aircraft the skin is a thin sheet of aluminum alloy or composite material fastened to the internal structure (spars, ribs, and stringers), and it carries a share of the structural loads in addition to shaping the airflow.
Plain English
The thin outer layer that covers the wing and gives it its smooth shape. It is what you actually see and touch when you walk up to the wing.
Context Anchor
Seen in aircraft structure diagrams, preflight inspections, and discussions of wing components.
Derivation
From the everyday word 'skin' meaning the outer covering of a body. Aircraft engineers borrowed the term because, like skin on a living thing, it forms the smooth outer layer over the internal frame.
Why Pilots Care
Damage or deformation of the skin can change the wing's shape, reduce lift, or allow structural failure under flight loads.
Analogy
Like the skin on a drum, aircraft skin is a thin outer surface stretched over a supporting structure. It is not just decoration; its condition matters to how the whole part works.
Intuition Check
Do not think of skin as just paint or a cosmetic covering. On a wing, the skin is the actual outer surface, and it may help support the loads of flight.
Example Sentence 1
During preflight, the pilot ran a hand along the wing skin and checked for any wrinkles, dents, or missing rivets.
Example Sentence 2
During preflight, check the wing skin for dents, cracks, or loose rivets.