旧友

1. Origins, structure, and basic meaning

• Structure: The relationship noun 旧友 (きゅうゆう) denotes a friend known from long ago.
• Basic usage: One may 旧友と再会する by chance or receive 旧友からの手紙.

2. Common pitfalls and similar expressions

• A friend from earlier days
  • It means a friend from long ago whose connection remains, not necessarily a former friend after a broken relationship.