I would like to use the word "addend" to describe the act of attaching an addendum, in the spirit of "amend", though not in the sense of correcting.
addend - attach additional information to
addended - altered to include additional information
Thoughts, anyone? This seems very logical for not being in the dictionary.
(I am already aware that this word has an existing definition in mathematical circles)
The problem with making up your own words for things is that other people won't understand you without a lengthy explanation.
"T'was brillig and the slithey toves..."