1. A person who makes a petition; one who formally requests something, especially in a legal context
The petitioner filed a lawsuit against the company.
O peticionário apresentou uma ação judicial contra a empresa.
2. A person who signs or presents a petition to an authority or government
The petitioners gathered signatures for the environmental cause.
Os peticionários coletaram assinaturas para a causa ambiental.
3. In law, the party who initiates legal proceedings by filing a petition
The petitioner must prove standing in the court.
O peticionário deve comprovar legitimidade processual no tribunal.