Определение firkin в Английский Язык Английский Язык словарь
A varying measure of capacity, usually being the fourth part of a barrel; specifically, a measure equal to nine imperial gallons
23 Hen. VIII, cap. 4... The barrel of beer is to hold 36 gallons, the kilderkin 18 gallons the firkin 9. But the barrel, kilderkin, and firkin of ale are to contain 32, 16, and 8 gallons.
A small wooden vessel or cask of indeterminate size, -- used for butter, lard, etc