外泊

1. Origins, structure, and basic meaning

• Structure: 外泊 is read as がいはく and means spending a night away from one's usual residence.
• Basic usage: It applies to an overnight absence that must be reported at a dormitory and to staying at a friend's house after a long interval.

2. Common pitfalls and similar expressions

• When advance notice is required
  • 外泊する場合 means a case of spending the night outside the dormitory and is linked here to advance reporting. Example: 学生寮で外泊する場合は事前に届け出ます。
• Staying at another home
  • After stating that someone stayed at a friend's house, 外泊しました summarizes it as a night away. Example: 友人の家に泊まり、久しぶりに外泊しました。