RSVP
From Longman Dictionary of Contemporary EnglishRSVPRSVP /ˌɑːr es viː ˈpiː/ TCNused on invitations to ask someone to replyFrom Longman Business DictionaryRSVPRSVP used on invitations to ask someone to replyOrigin RSVP (1800-1900) French répondez, s'il vous plaît “please reply”