- a measure of the opposition to the flow of an alternating current equal to the square root of the sum of the squares of the resistance and the reactance, expressed in ohms
- Also called: acoustic impedance the ratio of the sound pressure in a medium to the rate of alternating flow of the medium through a specified surface due to the sound wave
- Also called: mechanical impedance the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibration
WordReference Random House Unabridged Dictionary of American English © 2019
- Electricitythe total opposition to alternating current by an electric circuit, equal to the square root of the sum of the squares of the resistance and reactance of the circuit and usually expressed in ohms. Symbol: Z
- PhysicsAlso called mechanical impedance. the ratio of the force on a system undergoing simple harmonic motion to the velocity of the particles in the system.
- something that impedes;
an obstacle or hindrance.
- 1886; impede + -ance; term introduced by O. Heaviside