What is the difference between respondent and petitioner

"Petitioner" refers to the party who petitioned the  Court to review the case. This party is variously known as the petitioner or the appellant. "Respondent" refers to the party being sued or tried and is also known as the appellee. 

In another view, A petitioner is someone "asking" for something and the respondent is the one who "answers" .

Thanks 

NIRANJAN LENKA