A duty is an import fee (tariff) charged on goods entering a country, as specified in the country's tariff schedule.
Duties are usually imposed and collected by a country’s customs authority or agency. Different goods have different duties. Companies that want to sell goods internationally need to understand the tariff schedules of the countries where they plan to export.
The words tariffs and duty are often used interchangeably.
Check out the Canada Tariff Finder, a free tool that allows Canadian exporters to find the tariffs applicable to a specific good in a foreign market.