Real Dictionary

appendix
countable noun: Your appendix is a small closed tube inside your body which is attached to your digestive system.

appendix in American English
additional or supplementary material at the end of a book or other writing
noun: supplementary material at the end of a book, article, document, or other text, usually of an explanatory, statistical, or bibliographic nature

appendix in British English
noun: a body of separate additional material at the end of a book, magazine, etc, esp one that is documentary or explanatory