桶是一种圆柱形的容器，传统上以木材制成，称为木桶，但现时不少桶都是以金属或塑胶制成。桶通常用作盛载液体之用，如啤酒、原油等。

A barrel, cask, or tun is a hollow cylindrical container, traditionally made of wooden staves bound by wooden or metal hoops. Traditionally, the barrel was a standard size of measure referring to a set capacity or weight of a given commodity. For example, in the UK a barrel of beer refers to a quantity of 36 imperial gallons (160 L; 43 US gal). Wine was shipped in barrels of 119 litres (31 US gal; 26 imp gal).