Ad valorem duty is a term used in the import and export industry to refer to a tax that is levied on goods based on their value. There are several other synonyms for ad valorem duty. One synonym is "value-based tax," which refers to a tax that is calculated as a percentage of the value of goods. Another synonym is "percentage duty," which refers to a duty that is assessed as a certain percentage of the value of the imported or exported goods. Additionally, "tariff duty" is another synonym for the ad valorem duty, which is a tax that is levied on goods that are imported or exported between countries. These synonyms help to clarify the various types of taxes that may be levied on goods during international trade.