Editing Litre (section)

==Definition==

{{visualisation_litre_gram.svg}}
A litre is a cubic [[decimetre]], which is the volume of a cube 10 centimetres × 10 centimetres × 10 centimetres (1&nbsp;L ≡ 1&nbsp;dm<sup>3</sup> ≡ 1000&nbsp;cm<sup>3</sup>). Hence 1&nbsp;L ≡ 0.001&nbsp;[[Cubic metre|m<sup>3</sup>]] ≡ 1000&nbsp;[[cubic centimetre|cm<sup>3</sup>]]; and 1&nbsp;m<sup>3</sup> (i.e. a cubic metre, which is the [[SI]] unit for volume) is exactly 1000&nbsp;L.

From 1901 to 1964, the litre was defined as the volume of one kilogram of pure water at maximum density (+3.98&nbsp;°C){{citation needed|date=September 2023}} and [[standard pressure]]. The kilogram was in turn specified as the mass of the [[International Prototype of the Kilogram]] (a specific platinum/iridium cylinder) and was intended to be of the same mass as the 1&nbsp;litre of water referred to above. It was subsequently discovered that the cylinder was around 28 parts per million too large and thus, during this time, a litre was about {{val|1.000028|u=dm3}}. Additionally, the mass–volume relationship of water (as with any fluid) depends on temperature, pressure, purity and isotopic uniformity. In 1964, the definition relating the litre to mass was superseded by the current one. Although the litre is not an SI unit, it is accepted by the [[General Conference on Weights and Measures|CGPM]] (the standards body that defines the SI) for use with the SI. CGPM defines the litre and its acceptable symbols.

A litre is equal in volume to the [[stere|millistere]], an obsolete non-SI [[Metric system|metric]] unit formerly customarily used for [[dry measure]].