遺失

1. Origins, structure, and basic meaning

• Structure: 遺失 (いしつ) is a formal noun for losing property. 遺失に気づく concerns the event; 遺失物 is the item lost.
• Basic usage: A wallet loss is noticed and reported to station staff; a lost item's features are written on a reception form.

2. Common pitfalls and similar expressions

• Loss event recognized and lost property reported
  • The bare headword names the event; compound suffix 物 names the object itself. Its register often suits reports and administration more than everyday 紛失.