Retainage is an amount of money withheld from full payment until work is completed. It is withheld to assure that contractor will satisfy its obligations and complete a project.

尾款是留到工作完成后才支付的钱。尾款的目的是为了保证承包商履行义务干完工程。

Example:

There is a 5 percent retainage to be withheld on this project.

这项工程留有5%的余款。