From Longman Dictionary of Contemporary Englishlost propertyˌlost ˈproperty noun [uncountable] British English 1 DLOSE/CAN'T FINDthings that people have lost or accidentally left in a public place, which are kept until someone collects them2 (also Lost Property)DLOSE/CAN'T FIND a place where these things are kept until someone comes to claim them SYN lost-and-found American English Thankfully, someone had handed my bag into Lost Property.
Examples from the Corpus
lost property• Basically the police will regard the child as lost property to be returned as soon as possible.• He looks like lost property now.• If a name is available, librarians attempt to contact the owners of lost property.• Since plaintiffs naturally inclined to value their lost property exorbitantly, defendants did have reason to think seriously about restoring it. 