n. 25B6; noun
a mouse is a keyboard supplement : ADDITION, supplementation, supplementary, extra, add-on, accessory, adjunct, appendage; Computing peripheral.
a single room supplement : SURCHARGE, addition, increase.
a supplement to the essay : APPENDIX, addendum, end matter, tailpiece, codicil, postscript, addition, coda.
a special supplement with today's paper : PULL-OUT, insert, extra section.
25B6; verb they supplemented their incomes by spinning : AUGMENT, increase, add to, boost, swell, amplify, enlarge, top up.