How to say "empire" in Japanese

• 帝国ていこくCommon
  nounThe default word for an empire, any country ruled as one. Use it for historical empires such as the Roman Empire or for the generic concept in ordinary contexts.
  イギリス式しきの朝食ちょうしょくはイギリス帝国ていこくの建設けんせつ者しゃたちによって流行はやらせたものだ。↗

  The English breakfast was made popular by the architects of the British Empire.
• エンパイア
  nounA loanword matching 'empire' but far less common than 帝国. It appears mostly in proper names and borrowed titles, and is seldom the word you want in ordinary sentences.
• 皇国こうこく
  nounA dated, poetical term for the Empire of Japan — the Japanese Empire itself, or by extension Japan. Not used for foreign or generic empires.
• すめらみくに
  nounAlso a dated, poetical name for the Empire of Japan or Japan itself, normally written in kana alone. Not a general word for 'empire' in other senses.

Use 帝国 for empires in general; 「エンパイア」 mainly in borrowed names or set phrases; 皇国 and 「すめらみくに」 are dated, poetical ways of referring to the Japanese Empire (or Japan) itself.

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

• 帝国ていこくempire
• エンパイアempire
• 皇国こうこくEmpire (of Japan)
• 皇御国すめらみくにEmpire (of Japan)