A lien is a legal claim against an asset that is not cleared until an associated debt is paid. A lien is filed by a creditor, usually in situations where the asset is in the possession of the debtor.  The debtor cannot sell the asset until the lien has been cleared, which provides leverage by the creditor over the debtor.

An example of lien usage is when a debtor uses an asset as collateral on a loan; the lender files a lien on the asset with the applicable government entity, and releases the lien with the loan is fully paid.