Plain English Meaning
A soft leather filter cloth that catches water and dirt as fuel is poured through it, so only clean fuel reaches the aircraft tank.
Full Definition
A soft, porous leather cloth used as a filter when refueling an aircraft from a container or drum. Fuel is poured through the chamois, which traps water and solid contaminants while allowing clean fuel to pass through into the tank.
Context Anchor
Seen in refueling procedures, especially when fuel is being poured from cans, drums, or other portable containers into an aircraft.
Derivation
From the French chamois, a small mountain goat. The leather was originally made from its hide, and the name carried over to any soft, porous filtering leather, even when made from other animals today.
Why Pilots Care
Prevents introduction of lint or water into fuel systems and avoids scratching aircraft paint during cleaning.