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
Pound (mass) Jersey from the 14th century to the 19th century. It was equivalent to about 7,561 grains (490 grams). It may have been derived from the French livre poids de marc. The trone pound is one of a number of obsolete Scottish units of measurement. It was equivalent to between 21 and 28 avoirdupois ounces (about 600-800 grams). In many countries, upon the introduction of a metric system, the pound (or its translation) became an informal term for 500 grams. In German, the term is "Pfund", in French "livre", in Dutch "pond", in Spanish and Portuguese "libra", in Italian "libbra", and