A measure of capacity: 8 fluidrams. The imperial fluidounce is a measure containing 1 avoirdupois ounce, 437.5 grains, of distilled water at 15.6°C, and equals 28.4 ml; the U.S. fluidounce is 1/128 gallon, contains 454.6 grains of distilled water at 25°C, and equals 29.57 mL.
