a small barrel (= a round container with flat ends), used mainly for liquids, butter or fish （盛液体、黄油、鱼等的）小桶 a unit for measuring volume, equal to about 41 litres 桶（容量单位，约相当于 41 升）
Word OriginMiddle English ferdekyn, probably from the Middle Dutch diminutive of vierde ‘fourth’ (a firkin originally contained a quarter of a barrel).