As nouns the difference between addendum and appendage
is that addendum is something to be added; especially text added as an appendix or supplement to a document while appendage is an external body part that projects from the body.
addendum
English
Noun
(
wikipedia addendum)
(
en-noun)
Something to be added; especially text added as an appendix or supplement to a document.
A postscript.
(engineering) The height by which the tooth of a gear projects beyond (outside for external, or inside for internal) the standard pitch circle or pitch line.
appendage
English
Noun
(
en noun)
an external body part that projects from the body
a natural prolongation or projection from a part of any organism
a part that is joined to something larger
Synonyms
* extremity, member
* outgrowth, process