Other forms: blocs
A group that unites, especially for a political or economic purpose, is a bloc. The European Union is a bloc of countries that share common economic, social, and security policies.
A trade or political bloc is formed when countries (or states) unite around a common goal. The E.U., for example, sometimes operates almost as a single nation, especially when it comes to trading goods and services with other countries around the world. A voting bloc is a category of voters who tend to cast their ballots the same way; the "religious right" is one example of a voting bloc. The term comes from the French bloc, or "group."