What is Use Plaintiff?

Legal Definition
One for whbse use (benefit) an action is brought in the name of another. Thus, where the assignee of a chose in action is not allowed to sue in his own name, the action would be entitled "A. B. (the assignor) for the Use of C. D. (the assignee) against B. F." In this case, C. D. is called the "use plaintiff."
-- Black's Law Dictionary