1. An addition that makes changes to a will which is a legal document saying who gets one's money and property when someone dies.
2. A supplement modifying a will or revoking some provision of it.
3. Etymology: from Middle French codicille, from Latin codicillus, "a short writing, a small writing tablet"; from codicis a form of codex, from an earlier caudex, "book, book of laws"; literally, "a tree trunk" and so, a book made up of wooden tablets covered with wax for writing.