硬貨

1. Origins, structure, and basic meaning

• Structure: Spelling: 硬貨. Reading: こうか. Core meaning: coin.
• Basic usage: Representative examples: 券売機に百円硬貨を二枚入れた / 拾った硬貨を交番に届けた.

2. Common pitfalls and similar expressions

• Metal currency
  • 硬貨 means a coin made of metal and contrasts with paper currency, 紙幣. In counting money, the distinction concerns the form of currency rather than merely its shape.