Firkin

Firkin (dim. from four), an old measure of capacity containing 9 gallons (old ale and beer measure). But previous to the year 1803 it had two values, being estimated at 8 gallons in old ale measure, and at 9 in old beer measure. The firkin is equivalent to 9½ imperial gallons. The name is also applied to a small wooden cask, as for butter. This contains 56 lb.