The imperial unit is a system of measurement that was used primarily in the British Empire until the 20th century. There are several synonyms for the term "imperial unit," including British units, British Imperial System, traditional units, customary units, or simply the Imperial System. This system of measurement includes units of length, weight, and volume such as inches, feet, pounds, and gallons. While the metric system is now commonly used in many countries, some industries such as construction, agriculture, and cooking still rely on the imperial units for their day-to-day operations. Therefore, it's important to be familiar with the various synonyms for the imperial unit system.