The term "trade bloc" refers to a group of countries that have formalized an economic agreement to promote free trade within the bloc. There are several synonyms for this term, including "customs union," which refers to a trade bloc in which the member countries have a common external tariff for goods imported from outside the bloc. Another synonym is "regional trade agreement," which is a broader term that includes not only trade blocs but also other types of trade agreements between countries in a particular region. Finally, "economic community" is a synonym for trade bloc that emphasizes the economic integration and cooperation among member countries.