supplement - noun

textual matter that is added onto a publication; usually at the end

a quantity added (e.g. to make up for a deficiency)

a supplementary component that improves capability

supplement - verb

• add as a supplement to what seems insufficient
• serve as a supplement to
• add to the very end

supplement - thesaurus

accessory   addendum   affix   append   appurtenance   postscript   supplementation