From Longman Dictionary of Contemporary Englishpetitionerpe‧ti‧tion‧er /pəˈtɪʃənə $ -ər/ noun [countable] 1 ASK FOR something/ASK somebody TO DO somethingsomeone who writes or signs a petition2 lawSCL someone who asks for a legal case to be considered in a court of law
Examples from the Corpus
petitioner• In 1654 a council decision went against the Lutheran petitioners.• The only protection for the petitioner at the papal court is the Purse.• The divorce stage no longer requires a court appearance, except for the children's appointment in chambers, at which the petitioner attends.• There are actually also instances in which the petitioners describe a disposition as both.• The petitioner asks whether Seia can vindicate.• These petitioners were not charged with an attempt to overthrow the Government. 