"appendix" "attachment" "annex"

[herbivorie]

I found this definition of "appendix" here.
http://www.macmillandictionary.com/dictionary/british/appendix

"a section giving extra details at the end of a book, part of a book, or document"


If it's another document or leaflet, not a "section" in the same document, can't it be called an "appendix", and should it be an "attachment"?
How about an "annex"?

 

[MikeNewYork]

Usually, if it is a book, we would use "appendix". If it is an e-mail document, we would usually use "attachment. There is a dictionary definition for "annex" that covers these uses, but we usually use "annex" for an addition to a building.