United States customary units ounces. The fluid ounce derives its name originally from being the volume of one ounce avoirdupois of water, but in the US it is defined as of a US gallon. Consequently, a fluid ounce of water weighs about 1.041 ounces avoirdupois. The saying "a pint's a pound the world around" refers to 16 US fluid ounces of water weighing approximately (about 4% more than) one pound avoirdupois. An imperial pint of water weighs a pound and a quarter (20 oz). There are varying standards for barrel for some specific commodities, including 31 gal for beer, 40 gal for whiskey or
Anglo-Saxon pound Thomas Snelling writes that the division of the pound into 12 ounces was in use with the Romans, and the division of ounces into 20 pennyweights was introduced into France by Charlemagne, and then brought to England by William the Conqueror. The Latin word for "pound" is libra. The £ or ₤ is a stylised writing of the letter L, a short way of writing libra. This is similar to how a pound of mass is abbreviated "lb". Up until 1972, especially on typewriters or keyboards without a "£" symbol, it was common to write "L" or "l" instead of