kilogram

noun

ki·​lo·​gram ˈki-lə-ˌgram How to pronounce kilogram (audio) ˈkē-lə- How to pronounce kilogram (audio)
1
: the base unit of mass in the International System of Units that is defined by setting the fixed numerical value of Planck's constant to 6.62607015 x 10–34 joule seconds see Metric System Table
2
: a unit of force or weight equal to the weight of a kilogram mass under a gravitational attraction equal to that of the earth

Did you know?

The original concept of the kilogram, as the mass of a cubic decimeter of water (a bit more than a quart), was adopted as the base unit of mass by the new revolutionary government of France in 1793. In 1875, in the Treaty of the Meter, 17 countries, including the U.S., adopted the French kilogram as an international standard. In 1889 a new international standard for the kilogram, a metal bar made of platinum iridium, was agreed to; President Benjamin Harrison officially received the 1-kilogram cylinder for the U.S. in 1890. But no one uses that bar very often; for all practical purposes, a kilogram equals 2.2 pounds.

Examples of kilogram in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Under the original 2015 nuclear deal, Iran was allowed to enrich uranium only up to 3.67% purity and to maintain a uranium stockpile of 300 kilograms (661 pounds). Christopher Bodeen, Chicago Tribune, 14 Mar. 2025 From at least as early as January 2015 through September 2019, the U.S. Coast Guard interdicted at least four vessels, including two semi-submersibles, directly linked to Quintero Rengifo's organization, and involving more than 13,000 kilograms of cocaine, prosecutors said. Michael Loria, USA TODAY, 14 Mar. 2025 At the same time, financing the high cost of $5 to $8 per kilogram for current hydrogen outputs will be challenging if the IRA and 45V credits are modified or removed. Whitaker Irvin Jr., Forbes, 12 Mar. 2025 The operation also seized over a kilogram of cocaine, 53 grams of marijuana, roughly $73,000 in cash, nine firearms, five vehicles and a house believed bought with drug money and used for trafficking. Silas Morgan, Orlando Sentinel, 12 Mar. 2025 See All Example Sentences for kilogram

Word History

Etymology

French kilogramme, from kilo- + gramme gram

First Known Use

1797, in the meaning defined at sense 1

Time Traveler
The first known use of kilogram was in 1797

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Cite this Entry

“Kilogram.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/kilogram. Accessed 19 Mar. 2025.

Kids Definition

kilogram

noun
ki·​lo·​gram ˈkē-lə-ˌgram How to pronounce kilogram (audio) ˈkil-ə- How to pronounce kilogram (audio)
1
: the basic unit of mass in the metric system that has been accepted by international agreement and is nearly equal to the mass of 1000 cubic centimeters of water at its highest density see metric system
2
: the weight of a kilogram mass on the earth
he weighs 80 kilograms
see metric system

Medical Definition

kilogram

noun
ki·​lo·​gram
variants or chiefly British kilogramme
1
: the base unit of mass in the International System of Units that is equal to the mass of a prototype agreed upon by international convention and that is nearly equal to the mass of 1000 cubic centimeters of water at the temperature of its maximum density
2
: a unit of force equal to the weight of a kilogram mass under a gravitational attraction equal to that of the earth

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