A wine butt (from the medieval French and Italian botte) is a large cask (or barrel) holding two hogsheads of wine. A hogshead varied in size but today is most commonly 63 U.S. gallons (approx. 238.5 litres), so a butt is now usually 126 U.S. gallons or 108 imperial gallons (approx. 477 litres).
Traditionally, a butt of beer is 162 gallons or 613 litres, and how big a butt (or "pipe") of wine is depends on what kind of wine it is: