An Etymological Dictionary of Astronomy and Astrophysics

A metric unit of volume, formerly defined as the volume of one kilogram of pure water under standard conditions; now equal to 1 cubic decimeter (dm³); hence 1 liter = 0.001 m³ and 1000 liter = 1 m³.

See also: From Fr. litre, from litron, obsolete Fr. measure of capacity for grain, from M.L. litra, from Gk. litra “pound.”