"act of relying on someone or something," late 14c., recours, from Old French recours (13c.), from Latin recursus "a return, a retreat," literally "a running back, a going back," from past-participle stem of recurrere "run back, return," from re- "back, again" (see re-) + currere "to run" (from PIE root *kers- "to run"). Especially in have recourse (late 14c.) "apply for help, rely on for aid." As the word for the thing applied to for help, by late 15c. Sometimes in Middle English it also was used in an etymological sense of "a returning" from one state or place to another; "a flowing back," but these are obsolete.