accession, accessory, accompaniment, accumulative, addenda, addendum, additament, addition, additional, additory, additum, adjunct, adjuvant, annex, annexation, appanage, appendage, appendant, appurtenance, appurtenant, attachment, augment, augmentation, chain, coda, complement, component, concomitant, constituent, continuation, corollary, cumulative, elemental, extension, extrapolation, fixture, increase, increment, offshoot, pendant, reinforcement, side effect, side issue, summational, summative, supplement, tailpiece, undergirding