Plain English Meaning
A tough, springy metal made mostly of copper, used to build the tiny flexible parts inside instruments that measure pressure. It bends slightly when pressure changes, then springs back, over and over, without wearing out.
Full Definition
A copper alloy containing tin and a small amount of phosphorus, valued for its strength, springiness, corrosion resistance, and ability to hold a precise shape under repeated flexing. In flight instruments, it is commonly used to make the small diaphragms and capsules that sense pressure changes.
Context Anchor
In the Airspeed Indicator section, this term appears when describing the thin internal metal parts that move as changes inside the .