葉書

1. Origins, structure, and basic meaning

• Structure: 葉書(はがき) means a postcard for sending a short written message.
• Basic usage: It is used to send news from a trip or mail information for an entry or application.

2. Common pitfalls and similar expressions

• A postcard and a sealed letter
  • 葉書 is a card usually sent without an envelope; 封書 is a letter enclosed and sealed in an envelope.