The Collaborative International Dictionary of English v.0.48:
Petitioner \Pe*ti"tion*er\, n. One who presents a petition. [1913 Webster]WordNet (r) 3.0 (2006):
petitioner n 1: one praying humbly for something; "a suppliant for her favors" [syn: petitioner, suppliant, supplicant, requester] 2: someone who petitions a court for redress of a grievance or recovery of a right [syn: suer, petitioner]