kilogram

noun

ki·​lo·​gram ˈki-lə-ˌgram  ˈkē-lə- 

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

While payload capacity stats have fluctuated during development, the firm states a maximum payload capacity of 7,000 kilograms to low-Earth orbit. — Eric Berger, ArsTechnica, 28 Aug. 2026

The 8,400-pound (3,800 kilograms) MTG-I2 is the second imaging satellite in the Meteosat Third Generation network (hence the name). — Mike Wall, Space.com, 27 Aug. 2026

The group is also responsible for shootings, killings, kidnappings and assaults and the distribution of at least 340 kilograms of fentanyl or fentanyl-laced narcotics, Blanche said. — ABC News, 27 Aug. 2026

Each member of the group pleaded guilty to conspiracy to import five or more kilograms of cocaine, a crime that carries a minimum sentence of 10 years in prison and a maximum of life. — David Goodhue august 26, Miami Herald, 26 Aug. 2026

Word History

Etymology

French kilogramme, from kilo- + gramme gram

First Known Use

1797, in the meaning defined at sense 1

Phrases Containing kilogram

• kilogram-meter
• meter-kilogram-second

Rhymes for kilogram

• abraham
• anagram
• cablegram
• cofferdam
• dendrogram
• diagram
• diaphragm
• epigram
• hexagram
• histogram
• hologram
• instagram

Kids Definition

kilogram

noun

ki·​lo·​gram ˈkē-lə-ˌgram  ˈkil-ə- 

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

ˈkil-ə-ˌgram  ˈkē-lə- 

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