In English civil procedure, the term “respondent” has different meanings depending on the context in which it is used.
In the context of applications, a respondent is the party responding to an application made by an applicant. A claimant or a defendant can be a respondent to an application.
Example: In an application for security for costs, the party seeking security is the applicant. The party against whom security is sought is the respondent.
In the context of appeals, a respondent is usually the party who has obtained a judgment in their favour (whether claimant or defendant) which is subject to an appeal by an appellant.
Example: The Defendant has successfully defended the claim. The Claimant has appealed the decision from the High Court to the Court of Appeal. The Claimant is now the Appellant. The Defendant is now the Respondent.