Formal term for lost items, often used in official contexts such as police reports, station lost-and-found, and legal notices.
I picked up my umbrella at the station's lost-and-found office.
遺失物法に基づき、拾得者は速やかに届け出なければならない。
Under the Lost Property Act, the finder must report it promptly.
The station staff reported the umbrella they found as lost property.
The police keep lost property for a set period of time.
He showed his ID and claimed his lost property.