In culinary terms, papillote is a French term for a paper frill used to decorate the ends of bones, like on a rack of lamb or a crown roast. Pretty fancy.
Also fancy, but much more accessible to the home cook, is preparing food en papillote, meaning to bake something - usually meat and aromatic herbs - in a wrapping of parchment paper or tin foil. These luscious packages are also known as papillote themselves, and the whole thing is especially impressive if the papillote are baked in parchment and brought to the table to be opened by the diners.