A legal claim or security interest on an asset to secure repayment of a debt.
For example, when a lender finances a $75,000 commercial vehicle, it registers a lien against the truck's title. This lien prevents the borrower from selling the vehicle or using it as collateral elsewhere until the loan is fully repaid and the lien is discharged.
Why it matters: It secures the lender's position; a business cannot freely sell or refinance an asset until the lien is legally cleared.