How to say "billionaire" in Japanese

• ビリオネア
  nounA loanword straight from English 'billionaire'; it denotes someone worth a billion and keeps a foreign flavor, typical of business news and profiles of the world's richest people.
• 億万長者おくまんちょうじゃ
  nounThe general word for a very rich person, literally one rich in hundreds of millions; it covers multimillionaires and billionaires alike without naming a figure, and fits neutral talk about the wealthy.
  自分じぶんが億おく万まん長者ちょうじゃだと想像そうぞうしてごらん。↗

  Imagine yourself as a billionaire.
• 千万長者せんばんちょうじゃ
  nounThis really denotes a multimillionaire, not a billionaire; for 'billionaire' it is seldom the word you want, and it is uncommon enough that learners can safely pass it over.
• 大富豪だいふごう
  nounStresses enormous wealth — its first sense is 'extremely rich person' — so it suits a billionaire, though it describes riches in general rather than an exact figure; think of portraits of tycoons and magnates.

Choose 「ビリオネア」 for the direct loanword sense of billionaire; 億万長者 is the general term for a very rich person, covering multimillionaires and billionaires; 大富豪 stresses extreme wealth; 千万長者 is a marginal, chiefly multimillionaire option.

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

• ビリオネアbillionaire
• 億万長者おくまんちょうじゃbillionaire
• 千万長者せんばんちょうじゃmultimillionaire
• 大富豪だいふごうextremely rich person