Русско-англо-русский юридический словарь

A common external tariff must be introduced when a group of countries forms a customs union. [...] It is designed to end re-exportation; but it may also inhibit imports from countries outside the customs union and thereby diminish consumer choice and support protectionism of industries based within the customs union. (Wikipedia)

A common external tariff must be introduced when a group of countries forms a customs union. The same customs duties, import quotas, preferences or other non-tariff barriers to trade apply to all goods entering the area, regardless of which country within the area they are entering. It is designed to end re-exportation; but it may also inhibit imports from countries outside the customs union and thereby diminish consumer choice and support protectionism of industries based within the customs union. (Wikipedia)

In economics, protectionism is the economic policy of restraining trade between states (countries) through methods such as tariffs on imported goods, restrictive quotas, and a variety of other government regulations. (Wikipedia)