Firkin may refer to: Firkin (unit), small cask used for liquids, butter, salt, and sometimes fish: Firkin, a volume of beer; see English brewery cask units#Firkin Firkin Brewery, a chain of pubs in the United Kingdom Firkin Roos, an Australian rules football team in Britain; see Earls Court Kangaroos Firkin (aircraft), NATO reporting name for Su-47, a Russian experimental jet fighter