Firkin

The name means a fourth part, since a firkin first held a quarter of a barrel. Webster's 1913 dictionary says that in the United States it was a small cask of no fixed size used for butter and lard, while in England it was a measure of nine imperial gallons.

Because barrels varied, so did firkins: a quarter of a 31 1/2 gallon barrel is just under 8 gallons, and as a British butter weight a firkin was 56 pounds. So a firkin in a record may be a container, a volume or a weight, depending on time and place.