How to say "confederation" in Japanese

• 連邦れんぽうJLPT N1approx.Common
  nounCovers 'confederation' as a federation of states: one country made up of member states under a central federal government. This political sense is the word's core.
  アメリカ人あめりかじんは連邦れんぽう税ぜいと州税しゅうぜいの両方りょうほうを払はらっている。↗

  Americans pay both federal taxes and state taxes.
• 連合れんごうJLPT N2approx.Common
  noun, suru verb, transitive verb, intransitive verbCovers 'confederation' as a union, alliance, or combination of states or organizations rather than a single federal state. When the English stresses bodies joining together, this is the word to reach for.
  戦争せんそうは連合軍れんごうぐんの勝利しょうりに終おわった。↗

  The war ended in victory for the Allied Powers.

Use 連邦 for a confederation in the sense of a single federal state formed by member states, and 連合 for a confederation understood as a union, alliance, or combination of states or organizations.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 連邦れんぽうfederation (of states)
• 連合れんごうunion
• コンフェデレーションconfederation
• 合邦がっぽうmerger (of countries)