What is Auter Droit?

Legal Definition
Or more properly, Autre Droit, another's right. A man may sue Or be sued in another's right; this is the case with executors and administrators.
-- Bouviers Law Dictionary
Legal Definition
In right of another, e. pr., a trustee holds trust property in right of his cestui que trust. A prochein amy sues in right of an infant. 2 BL Comm. 176.
-- Black's Law Dictionary
Legal Definition
The right of another.
-- Ballentine's Law Dictionary