ad·den·dum
noun/əˈdendəm/
/əˈdendəm/
(plural addenda
(formal)/əˈdendə/
/əˈdendə/
)- a section of extra information that is added to something, especially to a book
（尤指书籍的）补遗，补篇 Word Originlate 17th cent.: Latin, ‘that which is to be added’, gerundive of addere, from ad- ‘to’ + the base of dare ‘put’.