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

To get around this, Sherburne designed the geometry of the wire to create a mismatch between its impedance and that of the antenna, which causes the signal to be reflected away from the power line. —IEEE Spectrum, 14 Dec. 2024

Natural behaviors like sneezing, chewing, or yawning can briefly break contact or, at a minimum, change the impedance of the earbud-skin connection. —IEEE Spectrum, 1 May 2019

The impedance scarcely varies from a nominal 6Ω over most of the frequency range. —Mark Sparrow, Forbes, 1 Nov. 2024

Maybe the game won't sync across platforms, and the impedance of having to start all over will be enough to prevent notable devolution. —Kevin Purdy, Ars Technica, 5 Sep. 2024

Word History

First Known Use

1886, in the meaning defined above

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