impedance

noun

im·​ped·​ance im-ˈpē-dᵊn(t)s 

: something that impedes : hindrance: such as

a

: the apparent opposition in an electrical circuit to the flow of an alternating current that is analogous to the actual electrical resistance to a direct current and that is the ratio of effective electromotive force to the effective current

b

: the ratio of the pressure to the volume displacement at a given surface in a sound-transmitting medium

Examples of impedance in a Sentence

Recent Examples on the Web

Electrochemical impedance results showed lower resistance, faster ion flow, and fewer corrosive by-products. —Neetika Walter, Interesting Engineering, 30 Aug. 2025

Plug And Play KUPID is amplifier-optimized, presenting a consistent impedance of over 4Ω to ensure smooth performance with a wide range of amplifiers, ​ including budget-friendly models and all-in-one amplifier and streamer systems. —Mark Sparrow, Forbes.com, 22 Aug. 2025

This rate of impedance change is measured by the sensor as a raw current signal. —Diya Dwarakanath, IEEE Spectrum, 11 Aug. 2025

To measure participants’ body fat, the researchers used a method called bioelectrical impedance analysis (BIA), which uses a device to measure the resistance of body tissue to a small electrical current. —Melissa Rudy, FOXNews.com, 28 June 2025

Word History

First Known Use

1886, in the meaning defined above

Rhymes for impedance

• credence

Medical Definition

impedance

noun

im·​ped·​ance im-ˈpēd-ᵊn(t)s 

1

: the apparent opposition in an electrical circuit to the flow of an alternating current that is analogous to the actual electrical resistance to a direct current and that is the ratio of effective electromotive force to the effective current

2

: the ratio of the pressure to the volume displacement at a given surface in a sound-transmitting medium

3

: opposition to blood flow in the circulatory system