億万長者

1. Origins, structure, and basic meaning

• Structure: 億万長者(おくまんちょうじゃ) denotes someone with immense wealth.
• Basic usage: It describes a novel's protagonist who built an immense fortune within their own lifetime.
  • 小説の主人公は一代で財を築いた億万長者だ。

2. Common pitfalls and similar expressions

• Great wealth and an exact amount
  • 億万長者 emphasizes immense wealth without specifying an exact amount. English billionaire normally means someone worth at least one billion units of a currency, so use that translation when the context supports it.