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early 15c., "intercession, intercessory prayer," from Middle French intervention or directly from Late Latin interventionem (nominative interventio) "an interposing," noun of action from past participle stem of Latin intervenire "to come between, interrupt," from inter- "between" (see inter-) + venire "come" (see venue).
intervention in·ter·ven·tion (ĭn'tər-věn'shən)
Interference so as to modify a process or situation.