lien noun Law : a right to keep the property of another person until a debt owed by that person is discharged.
escrow noun Law: 1 a bond, deed, or deposit kept by a third party until a specified condition has been fulfilled. 2 the state of being kept in this way.
A hire purchase agrrement is a typical example of a lien. The HP company has a lien on the goods until the final payment has been made.
The USA may use the term differently, as in the "mechanics lien", but the proceedure described by WDIK
customer has to deposit the money with an independant, who passes the monies on when the job is complete to satisfaction