Definition
A thin, tough membrane prepared from the outer layer of cattle intestine, historically used as the gas-holding fabric in lighter-than-air craft such as early airships and high-altitude balloons. It is exceptionally light, strong for its weight, and highly resistant to the leakage of hydrogen and helium through its surface.
Plain English
A very thin, very tough animal-based membrane that holds gas in without letting it leak out. It was used to make the inner gas bags inside old airships and balloons.
Context Anchor
Seen mainly in historical discussions of balloons, airships, and early aircraft materials.
Derivation
Named for its original use by goldbeaters -- craftsmen who hammered gold into extremely thin sheets (gold leaf). They placed the gold between layers of this membrane because it was tough enough to take repeated hammering without tearing. Aviation later borrowed the material for the same reasons: thin, light, and remarkably strong.
Why Pilots Care
Understanding the term helps when reading about the construction of historical lighter-than-air craft, where gas containment was the central engineering problem. It explains why early airships could hold hydrogen reliably despite the gas's tendency to escape through almost any material.
Grounding Statement
Picture a very thin natural film used like a gas-tight liner before plastic-coated fabrics were available.
Intuition Check
This does not mean human skin, and it does not mean gold-colored fabric. It means a prepared animal membrane once used because it was thin, tough, and could help contain gas.
Example Sentence 1
The gas cells inside early rigid airships were lined with goldbeater's skin to prevent hydrogen from leaking through the fabric.
Example Sentence 2
Early Zeppelin designers chose goldbeater's skin because it stayed flexible and airtight at altitude.