Since medieval times the term as a unit of measure has had various meanings throughout Europe, ranging from about 100 litres to about 1,000 litres. The name was derived in medieval times from the French , of unknown origin, but still in use, both in French and as derivations in many other languages such as Italian, Polish, and Spanish. In most countries such usage is obsolescent, increasingly superseded by SI units. As a result, the meaning of corresponding words and related concepts (vat, cask, keg etc.) in other languages often refers to a physical container rather than a known measure.