mid-14c., petiocioun, "a supplication or prayer," especially to a deity," from Anglo-French (early 14c.), from Old French peticion "request, petition" (12c., Modern French pétition) and directly from Latin petitionem (nominative petitio) "a blow, thrust, attack, aim; a seeking, searching," in law "a claim, suit," noun of action from past-participle stem of petere "to make for, go to; attack, assail; seek, strive after; ask for, beg, beseech, request; fetch; derive; demand, require," from PIE root *pet- "to rush; to fly."
Meaning "formal written request to a superior (earthly)" is attested from early 15c. In law, "a written application for an order of the court" (1737).
"make a request to," c. 1600, from petition (n.) or from or inspired by French pétittioner, from the noun in French. Related: Petitioned; petitioning.