relator

re·la·tor   (rĭ-lā'tər)    n.   One who relates or narrates: a relator of stories for children. Law A beneficially interested person on whose behalf an action is maintained by a sovereign power or a state.

Main Entry: re·la·tor
Pronunciation: rE-'lA-t&r
Function: noun
: a party other than the plaintiff upon whose information, knowledge, or relation of facts an action is brought when the right to bring the action is vested in another: as a : the private person who brings a qui tam action b : a party who has standing and on whose behalf a writ (as of mandamus) is petitioned for by the state as plaintiff <relator then filed…a petition in prohibition requesting this court to prohibit respondents from transferring the funds —State ex rel. Tate v. Turner, 789 South Western Reporter, Second Series 240 (1990)> —see also EX RELATIONE