Redemptio Operis
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Lab In Roman law, a contract for the hiring or letting of services or for the performance of a certain work in consideration of the payment of a stipulated price. It is the same centract as "locatio operis," but regarded from the standpoint of the one who is to do the work, and who is called "redemptor operis," while the hirer is called "locator operis"
See Mackeld.
Rom. Law, § 408.