Synonyms and related words :
accession, accessory, accompaniment, addenda, addendum, additament, addition, additive, additory, additum, adjunct, adjuvant, annex, annexation, appanage, appendage, appendant, appurtenance, appurtenant, attachment, augment, augmentation, by-product, coda, complement, concomitant, continuation, corollary, extension, extrapolation, fixture, increase, increment, offshoot, outgrowth, pendant, reinforcement, side effect, supplement, tailpiece, undergirding