Avoirdupois weight is a common measurement system for weight in the United States, but it may not be the only one you're familiar with. Some synonyms for avoirdupois weight include the imperial system, pounds, ounces, and stones. The imperial system is used primarily in the United Kingdom and includes units such as pounds and ounces. Pounds are also commonly used in the U.S. but are part of the avoirdupois weight system. Ounces are a small unit of weight often used in cooking, while stones are rarely used in the U.S. but are still common in the UK and Ireland. Regardless of the unit of measurement, it's important to understand the differences and conversions between them.