Coined by Heaviside from Latin impedīre 'to shackle the feet,' for the total opposition to alternating current in a circuit.
The effective resistance of an electric circuit or component to alternating current, combining ohmic resistance with reactance.
Coined by Oliver Heaviside from Latin impedīre 'to shackle the feet, hinder,' from in- 'in' + pes (stem ped-) 'foot.' Heaviside needed a term for the total opposition to current flow in AC circuits, which includes both resistance (energy loss) and reactance (energy storage). The metaphor is of fettered feet—current being hobbled.