[French R.S.V.P., formula written at the end of an invitation in order to request a reply, from r(épondez) s('il) v(ous) p(laît), please reply (literally, “reply, if you please”) : répondez, second person plural imperative of répondre, to answer, reply (from Old French respondre; see RESPOND) + si, if (from Old French, from Latin sī; see so- in the Appendix of Indo-European roots) + il, he, it (from Old French, from Latin ille, that one; see al- in the Appendix of Indo-European roots) + vous, you (from Old French, from Latin vōs; see ws in the Appendix of Indo-European roots) + plaît, third person present indicative of plaire, to please (from Old French, from Latin placēre; see plāk-¹ in the Appendix of Indo-European roots).]