A troy ounce is a unit of measurement used to weigh precious metals like gold, silver, and platinum. However, there are various synonyms for this term, including the troy weight or apothecary weight. This weight system is based on the grain, with a troy ounce equivalent to 480 grains or about 31.1 grams. Another synonym for troy ounce is Tower ounce, which was used in England before the adoption of the metric system. The Troy weight system also includes other denominations such as grams, pennyweight, and carats. Knowing these synonyms can be helpful when buying or selling precious metals, ensuring that you understand the weight measurement system used during the transaction.