Русско-англо-русский юридический словарь

retention money. Payment for a service or product that is withheld pending the completion of some specified condition. For example, when a manufacturing business purchases production machinery from a supplier, they might withhold some percentage of payment due as retention money until the machines are successfully installed and operational. (BusinessDictionary)

What is retention money?

It depends on the situation, but generally, this is money that is held back that would otherwise be paid, until the other party performs some service or task.

For example, in the construction business, it is common that a series of payments is made over time, with the caveat that the last 10% of the payments (for example) is withheld until the job is complete. This way, the contractor can pay his costs during construction, but obviously doesn't get the entire amount until the job is done. (answers.yahoo.com)