Any of various units of volume or capacity. In the U.S. Customary System it varies,as a liquid measure,from 31 to 42 gallons(120 to 159 liters) as established by law or usage.

• 一桶液量之单位许多体积或容量单位的任一个。在美国惯用系统中，它作为液体测量单位，数值在被法规或惯用法确立的数值31加仑到42加仑（120到159升）之间变动。