lost property

Short definition from Wiktionary

Noun

1. 1
   A help desk or department in a store, mall, or other such facility where customers who have lost an item can inquire as to whether it has been found and turned in; a lost and found.
2. 2
   Property that is found in such a state as to make it likely that the original owner unintentionally ceased to be in possession of the property, and would be unable to locate the property.