units of volume
A barrel is a unit of volume used to measure liquids, particularly petroleum. For oil and petroleum products, a barrel equals 158.98 liters or 35 Imperial gallons (42 US gallons). For beer, a barrel equals 163.66 liters or 36 Imperial gallons (43.24 US gallons). For dry goods (such as grain), a barrel equals 0.1156 cubic meter or 3.180 bushels (3.28 US bushels).
A bushel is a unit of dry measure equal in volume to 8 imperial gallons or 64 pints (36.5 liters), and to four pecks. It is traditionally used to measure grain and fruit. The name comes from a word in Old French for a much smaller measure, "the amount one can hold in the hand."
Gallon (gal) is the name of various units of volume. The US gallon is 0.003785 m2. The UK gallon, the volume of 10 lbf of pure water under specified conditions, is 0.004546 m3 or 1.201 US gallons.
A gill (gi) is any of various units of volume, usually equalling one-fourth of a pint. The US gill is 0.1183 liters; the Imperial gill is 0.1421 liters.
The liter (l) is a metric unit of volume originally defined as that of 1 kilogram of water at the temperature of maximum density (1.000028 dm3), but redefined in 1964 as exactly equal to 1 cubic decimeter (= 1 dm3). A liter is equivalent to 0.22 imperial gallons or 0.2642 US gallons. The liter is not recommended for use alongside SI units.
The pint is a unit of liquid capacity. One pint is equal to 1/8 of a gallon, 1/2 of a quart, 1.201 US pint, or 0.568 liter.