French term for ton or barrel, from which the today internationally common name Tonnellerie (cooperage) is derived. In the Middle Ages, tonneau was a frequently used type of barrel in France with a volume of 900 litres, which is mentioned in very many old writings in connection with wine. It corresponded to the English tun (clay). Tonneau was also a ship's measure, comparable to today's gross register tons. The barrel was too large for ship transport, so it was divided into two douils of 450 litres each or four oxhofts of 225 litres each. Today, tonneau (also called batch in the Médoc) is usually used as the unit of measurement, which also corresponds to 100 cases or 1,200 bottles of wine. There are, however, barrel producers who make barrels of various sizes under this designation. The picture on the left shows a tonneau with a volume of 500 litres and in comparison a barrique barrel. See also under barrel types and hollow dimensions.