Barrel (oil, bbl)
The oil barrel, symbol bbl, is a unit of volume commonly used in the petroleum industry. Its origins date back to the mid-19th century, when the American oil industry adopted the wooden barrel as a standard for storage and transportation. In 1866, the barrel was officially set at 42 US gallons (about 159 liters) to unify trade and pricing. Although physical barrels are no longer used, the “barrel” remains a widely recognized standard for oil production, consumption, and trading. The oil barrel is commonly referenced in discussions of energy, economics, and industrial development as a non-metric unit of volume.
US Pint (pt)
The US pint, symbolized as pt, is equal to 1/8 of a US gallon, or approximately 473 milliliters. Derived from British units, it became standardized in the US after independence. Pints are commonly used for beverages like beer and milk in the United States. Unlike the British imperial pint (568 mL), the US pint is smaller, creating distinctions in international trade and cultural habits. Despite metrication globally, the pint remains a familiar and enduring unit of measurement in everyday American life.