The avoirdupois ounce is a unit of weight commonly used in the United States and other countries that follow the avoirdupois system. It is defined as exactly 28.3495 grams. This measurement is primarily used for everyday items, such as food and other goods, making it a practical unit for consumers and retailers. In the avoirdupois system, there are 16 ounces in a pound, which means that one pound equals approximately 453.592 grams. The term "avoirdupois" comes from Middle French, meaning "goods of weight," and it has been in use since the 14th century, influencing various fields, including commerce and cooking.