Liter

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late 18th century: from French, alteration of litron (an obsolete measure of capacity), via medieval Latin from Greek litra, a Sicilian monetary unit.

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liter (n.)

unit of capacity in the metric system, 1797, from French litre (1793), from litron, name of an obsolete French measure of capacity for grain (16c.), from Medieval Latin litra, from Greek litra "pound" (unit of weight), which apparently is from the same Sicilian Italic source as Latin libra (see Libra).