2
affix(noun, addition, extension, supplement, adjunct)
2
afterthought(noun, addition, supplement)
2
afterword(noun, supplement)
2
augment
2
back matter(noun, document)
2
boost(noun, extra, supplement, appendage, add-on)
2
companion(noun, accompaniment)
2
concomitant
2
enclosure(noun, supplement)
2
enhancement(noun, increase, extra, addition, supplement)
2
expansion(noun, increase, delay, development, spread)
2
gain(noun, extra, supplement, appendage, add-on)
2
garnish(noun, accompaniment, adjunct)
2
raise(noun, extra, supplement, appendage, add-on)
2
rise(noun, extra, supplement, appendage, add-on)
2
side note
2
subscript(noun, sequel)
2
subsidiary(noun, increase, extra, addition, extension)
1
accident
1
accidental
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APASmart Define. (2015). addendum thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/addendum/thesaurus/synonyms
ChicagoSmart Define. 2015. "addendum thesaurus" https://smartdefine.org/addendum/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, addendum thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/addendum/thesaurus/synonyms>.
MLASmart Define. "addendum thesaurus" 13 April 2015. Web. 21 September 2026. <https://smartdefine.org/addendum/thesaurus/synonyms>