Trade Diversion:Trade diversion is the shift in trade from a more efficient non-member country to a less efficient member country within a trade agreement, due to the preferential tariff treatment given to member countries.
Comparative Advantage:Comparative advantage is the ability of a country to produce a good more efficiently than another country, leading to specialization and increased trade between the countries.
Customs Union: A customs union is a type of trade agreement where member countries eliminate tariffs on trade between themselves and adopt a common external tariff on imports from non-member countries.