əˈdendəm, aˈ- noun
( plural adden·da -də ; see sense 3 )
Etymology: Latin, neuter of addendus, gerundive of addere to add — more at add
1. : a thing that is added or is to be added : addition , supplement
as an addendum … let me point out one fact — A.C.Eurich
2.
a. : an explanation, comment, or additional item appended to a book
these addenda fill six pages
b. : a list or section consisting of added material ; especially : a supplement to a book sometimes issued separately
the new edition includes a 10-page addendum
— sometimes plural but sing. in constr.
the addenda contains many new words
3. plural addendums : the part of a tooth of a gear wheel between pitch line and extreme point of the tooth ; also : the distance between pitch line and addendum circle — compare dedendum
4. addenda plural : accessories, appurtenances
a dozen exciting addenda to culinary art — Holiday