This term refers to the person or party who filed the original lawsuit. Defined in the rules as, “The person or entity [who] files the first petition.” ARFLP Rule 3(f)(1). In family law matters, some people develop an emotional attachment to being the Petitioner vs the Respondent (see term Respondent for related information). This usually dictates the order in which you present your story at trial. See also Respondent.