First recorded in 1861; named after G. S. Ohm
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.
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Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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
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
For example, it means also 66that one volt will send a current of one ampere through a resistance of one ohm.
From Letters of a Radio-Engineer to His Son by John Mills
“We design our products and services to protect people’s privacy because only DNA is harder to anonymize than human movements,” the company’s website says, quoting Georgetown law and privacy expert Paul Ohm.
From The Wall Street Journal ● Jul. 21, 2026
But Ohm is such a misanthrope that he’d never go to a cheery beach resort.
From Los Angeles Times ● Apr. 30, 2026
Ohm said prosecutors have “sometimes blurred” that line, including in the Seefrieds’ case.
From Seattle Times ● Jun. 14, 2022
The companies, Best Electricity Supply, Ohm Energy, UGS Energy, SilverCloud Energy and iSwitch supplied around 9% of Singapore's electricity consumers, with their closures a setback to the country's power market liberalisation.
From Reuters ● Dec. 9, 2021
His resignation was accepted with regrets by the ministry, but with a distinct expression that Ohm must not expect other than a gymnasium position.
From The Popes and Science The History of the Papal Relations to Science During the Middle Ages and Down to Our Own Time by James J. Walsh
The absolute value of the difference between the actual and nominal resistance should not exceed the stated variability, so, with the resistance in ohms,
From Textbooks ● Feb. 13, 2015
When the current in a circuit is 40 amperes, the resistance is 10 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
In persons suffering from nervous anxiety, it decreases to five thousand and even down to a thousand ohms in cases of hysteria.
From The Social Gangster by Arthur B. (Arthur Benjamin) Reeve
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
