Codicil

Noun

 * 1)  An addition or supplement that explains, modifies, or revokes a will or part of one.
 * 2) * 2005 : If Nick answered a question Wani listened to him and then gave a flat little codicil or correction. - Alan Hollinghurst, The Line of Beauty, (Bloomsbury Publishing, paperback edition, 378)

Thesaurus
PS, Parthian shot, addendum, affix, afterthought, allonge, appendix, attested copy, back matter, bequeathal, bequest, chorus, coda, colophon, commentary, conclusion, consequence, continuance, continuation, devise, double take, dying words, enclitic, envoi, epilogue, follow-through, follow-up, infix, inheritance, interlineation, interpolation, last words, legacy, marginalia, note, parting shot, peroration, postface, postfix, postlude, postscript, prefix, probate, proclitic, refrain, rider, scholia, second thought, sequel, sequela, sequelae, sequelant, sequent, sequitur, subscript, suffix, supplement, swan song, tag, tail, testament, will