# impedance

[ im-peed-ns ]
/ ɪmˈpid ns /

### noun

Electricity. the 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
Also called mechanical impedance. Physics. 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.

## QUIZZES

#### TAKE THIS QUIZ IF A DAZZLING VOCABULARY IS YOUR DESIDERATUM!

Have the Words of the Day from October 19–25, 2020, made an indelible mark on your memory? Take the quiz to find out!
Question 1 of 7
What does “clement” mean?

## Origin ofimpedance

1886; impede + -ance; term introduced by O. Heaviside

## OTHER WORDS FROM impedance

self-im·ped·ance, noun

## Words nearby impedance

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

## British Dictionary definitions for impedance

impedance
/ (ɪmˈpiːdəns) /

### noun

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 ohmsSymbol: Z
a component that offers impedance
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 waveSymbol: Z a
Also called: mechanical impedance the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibrationSymbol: Z m
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Scientific definitions for impedance

impedance
[ ĭm-pēdns ]

A measure of the opposition to the flow of alternating current through a circuit. Impedance is measured in ohms. The resistance of a circuit to direct current (also measured in ohms) is generally not the same as its impedance, due to the effects of capacitance and induction in and among the components of the circuit. See also impedance matching.