同封

1. Origins, structure, and basic meaning

• Structure: 同封 is read as どうふう and is a noun and する verb for enclosing another document or item in the same letter or envelope.
• Basic usage: Enclosing an application and return envelope appears in 申込書と返信用封筒を同封する, while a map enclosed with an invitation appears in 案内状に同封された地図.

2. Common pitfalls and similar expressions

• Active and passive modification
  • The sender uses 同封する for enclosing items, while an item included with something is modified by 同封された.
• Difference from 添付
  • Unlike the broad word for attaching material to a document or electronic file, this term strongly suggests placing it inside the same envelope or mailing.