Plain English Meaning
It is a way of calming down a moving needle or pointer in an instrument by letting a magnet quietly drag on it, so it settles to a steady reading instead of swinging back and forth.
Full Definition
A method of slowing or stabilizing the motion of a moving instrument component by using small circulating electrical currents (eddy currents) that are induced when a conductive disc or vane moves through a magnetic field. The induced currents create a magnetic drag that opposes the motion, smoothing out oscillations without using friction or springs.
Context Anchor
Seen in aircraft instrument construction and maintenance, especially when explaining how mechanical instrument pointers are kept steady.
Derivation
An 'eddy' is a small swirling motion, like a whirlpool in water. The term was borrowed for because the induced currents swirl in small loops inside the . '' comes from an older sense of 'damp' meaning to deaden or muffle — the same idea as damping a vibrating string. Together: tiny swirling currents that quietly muffle motion.