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.
The latter means that every token can, at minimum, be redeemed for one kilogram of nutrient-rich potting soil. Alexandra Harrell, Sourcing Journal, 24 Sep. 2025 The vessel was allegedly carrying 1,000 kilograms of cocaine when it was intercepted approximately 80 nautical miles south of Isla Beata, a small Dominican island. Adeola Adeosun, MSNBC Newsweek, 22 Sep. 2025 These full-size robots stand around human height, with the GR-1 weighing approximately 55 kilograms and offering 44 degrees of freedom. Kaif Shaikh, Interesting Engineering, 22 Sep. 2025 Soueif, 68, lost 30 kilograms (66 lbs) in the process and only ended the strike after she was given assurances that the British government was prioritizing the release of her son, rights group Amnesty International said. Mostafa Salem, CNN Money, 22 Sep. 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 1 Oct. 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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