p/s and RSVP??

I've always wondered, what does p/s and RSVP stand for?i mean, i know what it's suppose to mean, as in p/s is used after u write something, and left something out. so you put p/s. and RSVP is for reservations. and seats. to reserve. but what does it stand for?i remember when i was in form 2, my English teacher was writing a informal letter on the white board, and she wrote p/s...... then she asked us, if we all know what it means, and me, being the smart one, answered, "is it please".hahahahahahaahhahahaha...omggg!now when i think back, i feel so stupid for asking that. and my teacher and the whole class laughed!wtf right?ok, those morons who laughed at me, you guys din even know what the hell p/s is used for ok?at least i knew how to use it, jut din know what "p/s" stands for. so dun laugh!ahhahahaha... i can laugh at myself though!hahahaahahhaahahahahahahahahah...anyway, that was p/s. then yesterday i asked my mom(also English teacher)hehehe.. i asked her what does p/s stand for, then she said "post-script".sayang you mama. at least i got the answer i wanted. then i asked her what bout RSVP?ok, this one mom said it's a french term for reservations. which was exactly what Chris told me the other day. cz i asked him and bebeh too. at first he made up something bout p/s which made us all laugh. then RSVP he said its french. then were thinking thinking, maybe it's "reservoir sil vous plait"?cz sil vous plait is please ma in french. so prob the "r" stands for reservoir or reseveree" i dunno. i haven't mastered my french yet. prob ask my lec this Monday. hehehehehehe.hahaha..anyway, at least i know what does p/s stand for. so it means "p/s: i love you" means "post-script: i love you. "haahhahahaahahah.. i know i sound dam lame. ok bye!:p