Barrel (unit)

A barrel is a unit of measurement commonly used to quantify the volume of liquids, particularly in the oil and brewing industries. The definition of a barrel can vary depending on the substance being measured: 1. **Oil**: In the oil industry, a barrel is defined as 42 US gallons, which is approximately 159 liters. 2. **Beer**: In brewing, a barrel can refer to different volumes depending on the region or specific context.