Applicant是上诉人

Respondent是被上诉人，被告。

可参考如下英文释义：

Applicant is one who applies for something; one who makes request; a petitioner

Respondent is (legal) person who answers for the defendant in a case before a court. In some legal systems, when one appeals a criminal case, one names the original court as defendant, but the state is the respondent.