Common name in England but also in other countries (also Demijon, Demi John, Demingnon, Lady Jane) for a balloon bottle (wicker bottle) The name is a malapropism of Dame-Jeanne (see the meaning of the name there), the Italian equivalent is Damigiana, the Argentine Damajuana. Such vessels with a volume of 45 litres were/are used in Portugal and Spain for the maturing of sherry and port wine and the contents are then decanted into normal bottles before being marketed. In German Lower Saxony, Demijon in the Low German dialect is still used today for large belly bottles, which are mostly used for storing and transporting brandy and rum. See also a list of all bottle designations under Bottles and generally under Wine Vessels.
I have great respect for the scope and quality of the wein.plus encyclopaedia. It is a unique place to go for crisp, sound information on terms from the world of wine.
Dr. Edgar Müller
Dozent, Önologe und Weinbauberater, Bad Kreuznach