1. In the International System of Units, the base unit of mass; the mass of a specific cylinder of platinum-iridium alloy kept at the International Bureau of Weights and Measures in France. Symbol: kg
  2. (proscribed) Hence, the unit of weight such that one-kilogram mass is also a one-kilogram weight.

Usage notes

  • (proscribed, unit of weight): The use of the kilogram as a unit of weight is somewhat imprecise, as the weight of a one-kilogram mass will depend on its location. It is therefore frequently proscribed, but is nonetheless in wide use. (The same imprecision and proscription also occur with many other words pertaining to weight and mass, such as the verb .)


New World Encyclopedia writers and editors copied and adjusted this Wiktionary entry in accordance with NWE standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit for this article is due to both New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list acceptable citing formats.The history of earlier contributions at Wiktionary is accessible to researchers here: