A slice of bread weighs 1 ounce, which is 28.34 grams. An ounce is the smallest standard American measurement of weight and is equal to 1/16th of a pound.
Other items or collections of items which weigh 1 ounce include: 28 paper clips, five U.S. quarters, and a compact disc (CD). An ounce is also a measurement of volume. A liquid ounce is an American measurement that is equal to 29.57 milliliters, or 1/8th of a cup.
Both liquid and solid ounces are a part of the United States customary units, a set of measurements which were derived from the British Imperial units. U.S. or Imperial units bear similar names, but differ slightly in size; a gallon of milk in America is not the same as a gallon of milk in England.