1. Add as a supplement to what seems insufficient
   "supplement your diet"
    
2. Serve as a supplement to
   "Vitamins supplemented his meagre diet"
    
3. Add to the very end
   "They supplemented the report with new data";
   - append, add on, affix

1. A supplementary component that improves capability
   "The smartphone case was sold as an optional supplement";
   - accessory, appurtenance, add-on, bolt-on
    
2. A quantity added (e.g. to make up for a deficiency)
   "The vitamin supplement was recommended to address the nutritional deficiency";
   - supplementation
    
3. Textual matter that is added onto a publication; usually at the end
   "The research paper included a supplement with additional data";
   - addendum, postscript
    
4. (geometry) an angle that, when added to a given angle, makes 180 degrees
   "The supplement of a 30-degree angle is 150 degrees"

Derived forms: supplements, supplementing, supplemented

Type of: add, attach, be, component, comprise, constituent, constitute, element, increase, increment, make up, matter, represent

Part of: back matter, end matter

Encyclopedia: Supplement