The imperial system refers to a system of measurement that was popularized during the times of the British Empire and is still used in some countries today. Synonyms for this system include the British measurement system, the old English system, and the customary system. These synonyms refer to the same measurement units used in the imperial system such as inches, feet, yards, and miles for length; ounces, pounds, and tons for weight; and pints, quarts, and gallons for volume. Despite the prevalence of the metric system, the imperial system continues to be used in certain countries including the United States, which makes it important to know these synonyms.