1.textual matter that is added onto a publication; usually at the end
2.a quantity added (e.g. to make up for a deficiency)
3.a supplementary component that improves capability
1.add as a supplement to what seems insufficient;
supplement your diet
2.serve as a supplement to;
Vitamins supplemented his meager diet
3.add to the very end;
He appended a glossary to his novel where he used an invented language