In law, lien is the broadest term for any sort of charge or encumbrance against an item of property that secures the payment of a debt or performance of some other obligation.
Liens can be consensual or non-consensual. Consensual liens are imposed by a contract between the creditor and the debtor. These liens include:
- security interests;
- chattel mortgages
- tax liens, imposed to secure payment of a tax;
- attorney's liens, against funds and documents to secure payment of fees;
- mechanic's liens, which secure payment for work done on property or land;
- judgment liens, imposed to secure payment of a judgment
- maritime liens, imposed on ships by the law of admiralty.
Perfecting a lien is an important part of the task of protecting the secured creditor's interest in the property. A perfected lien is valid, even against a trustee in bankruptcy; an unperfected lien is not.