Some common units used for water measurements are ounce, fluid ounce, cup, pint and gallon. Other measurements are liter and milliliter. Fluid ounce and ounce are different because fluid ounce measures volume while ounce measures mass, but volume and mass are the same in the case of water.
Eight fluid ounces makes up a cup. Another name for a cup in the United States is a glass. A pint is two cups; a quart is four cups, or two pints and a gallon is 16 cups, eight pints, or four quarts. These are standards used in the United States. For example, a British gallon is larger than a U.S. gallon. An Imperial gallon holds 4.546 09 liters of liquid, based on 10 pounds of water distilled under very strict criteria.
A fluid ounce is about 30 milliliters, while a pint is about 473 milliliters. A quart is about 946 milliliters. A gill is 1/4 of a pint, or 1/2 cup.
The weight of water is also measured in ounces, tons and pounds. It's also measured in grams and kilograms. Originally, a gram was the mass of a cubic centimeter of purified water. A fathom measures the depth of water at sea. An avoirdupois dram is 1.7718 of a gram, while an apothecaries' dram is 3.8879 of a gram.