1 a large, round, wooden, plastic or metal container for liquids, that has a flat top and bottom and is wider in the middle 大桶: a beer/wine barrel 啤酒／葡萄酒桶

2 a unit of measurement in the oil industry equal to approximately 159 litres 桶（石油计量单位，大致相当于159升）: The price of oil is usually given per barrel. 油价通常按桶报价。

3 the long metal part of a gun like a tube through which the bullets are fired 枪管