RSVP
RSVP is an initialism derived from the French phrase "Répondez s'il vous plaît", meaning "please respond" (literally "respond if it pleases you"). It is typically used to request confirmation of an invitation. Occasionally, the phrase "please RSVP" is used, which is a case of RAS syndrome (a pleonasm), as "s'il vous plaît" means "please".
"RSVP" is no longer widely used in France, where it is considered formal and old-fashioned; it is more common to use "Réponse attendue avant le …", meaning "[Your] answer is expected before …" In French-speaking parts of Canada, such as Quebec, it is still commonly used. In addition, the French initialism "SVP" is frequently used to represent "S'il vous plaît" ("please").