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• ohm
  ohm

  noun

  the standard unit of electrical resistance in the International System of Units (SI), formally defined to be the electrical resistance between two points of a conductor when a constant potential difference applied between these points produces in this conductor a current of one ampere. The resistance in ohms is numerically equal to the magnitude of the potential difference. Ω
• Ohm
  Ohm

  noun

  Georg Simon, 1787–1854, German physicist.

ohm

¹ American  

[ohm] / oʊm /

noun

ohms plural

1. the standard unit of electrical resistance in the International System of Units (SI), formally defined to be the electrical resistance between two points of a conductor when a constant potential difference applied between these points produces in this conductor a current of one ampere. The resistance in ohms is numerically equal to the magnitude of the potential difference. Ω

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Ohm ² American  

[ohm] / oʊm /

noun

1. Georg Simon, 1787–1854, German physicist.

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ohm ¹ British  

/ əʊm /

noun

1.  Ω.  the derived SI unit of electrical resistance; the resistance between two points on a conductor when a constant potential difference of 1 volt between them produces a current of 1 ampere

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Ohm ² British  

/ əʊm /

noun

1. Georg Simon (ˈɡeːɔrk ˈziːmɔn). 1787–1854, German physicist, who formulated the law named after him

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ohm ¹ Scientific  

/ ōm /

1. The SI derived unit used to measure the electrical resistance of a material or an electrical device. One ohm is equal to the resistance of a conductor through which a current of one ampere flows when a potential difference of one volt is applied to it.

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Ohm ² Scientific  

1. German physicist who discovered the relationship between voltage, current, and resistance in an electrical circuit, now known as Ohm's law. The ohm unit of electrical resistance is named for him.

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ohm Cultural  

1. The unit of electrical resistance, named after the nineteenth-century German physicist Georg Ohm.

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Other Word Forms

Derived Forms

• ohmic
  adjective

Inflected Forms

Nouns

• ohms
  plural

Etymology

Origin of ohm

First recorded in 1861; named after G. S. Ohm

Explanation

An ohm is a unit of electricity — or more specifically, a unit of electrical resistance. The resistance of good electrical conductors, like copper, is measured in ohms. When it comes to electricity, there are many ways to measure it, including amps of current and volts of voltage. Ohms specifically measure the amount of resistance in an electrical current, an idea that's easiest to understand in terms of plumbing. Picture water flowing through a pipe; the water pressure is the voltage, the rate at which it flows is the current, and the size of the pipe is the resistance. Ohm is named for Georg S. Ohm, the physicist who discovered the relationship between current, voltage, and resistance.

Example Sentences

See Examples For:

ohm Ohm ohms

Because USB cables are terrible – just think about the number of bell wire USB cables with 10k ohm resistance.

From The Verge ● Mar. 8, 2022

Sometimes I just let the water pummel the top of my head and listen to the ohm of the fan’s whir, losing myself in the hug of its hum.

From Washington Post ● Oct. 27, 2021

"For illustration, here are some shorties which we'd call real $7 words, and wouldn't use here at this time without explanation: adit, erg, ergo, ohm, gloze, cozen, griff, modal, mure, snash, viable."

From Time Magazine Archive

It can be hooked up with a hi-�fi, responds with a special yellow bulb when it hears the voice of Mick Jagger, looked very much at ohm last summer performing in a Manhattan discotheque.

From Time Magazine Archive

They had discovered the X ray, the cathode ray, the electron, and radioactivity, invented the ohm, the watt, the Kelvin, the joule, the amp, and the little erg.

From "A Short History of Nearly Everything" by Bill Bryson

Those attorneys — Tezira Abe and Eugene Ohm — did not respond to a request for comment after the hearing.

From Los Angeles Times ● Apr. 27, 2026

Ohm said prosecutors have “sometimes blurred” that line, including in the Seefrieds’ case.

From Seattle Times ● Jun. 14, 2022

In Asia, power provider Ohm Energy said on its website that it had exited the retail electricity market in Singapore on Friday, the third company to do so in recent weeks.

From Reuters ● Oct. 18, 2021

“I just hope that I can help some people from dying of disease and miscarriage,” Ms. Radi Ohm said.

From New York Times ● Sep. 14, 2021

The relation between these is expressed by the well-known law of Ohm, which runs: A current of electricity is directly proportional to the electromotive force and inversely proportional to the resistance of the circuit.

From The Story of Electricity by Munro, John

When the current in a circuit is 40 amperes, the resistance is 10 ohms.

From Textbooks ● Feb. 13, 2015

The current in a circuit varies inversely with its resistance measured in ohms.

From Textbooks ● Feb. 13, 2015

Unfortunately, when you buy a resistor, you can’t get one that is exactly 1000 ohms; rather, it is guaranteed to be only within 10 percent of that value.

From Salon ● Feb. 16, 2013

Electricity is sold in kilowatt-hours but electricity terminology spans other units like volts, amperes, and ohms.

From Slate ● Oct. 14, 2011

Fig. 41a. coil is provided, and this should be wound with No. 47 S.S.C. copper wire for a resistance of about 2000 ohms.

From Wireless Transmission of Photographs Second Edition, Revised and Enlarged 1919 by Martin, Marcus J.