(a.) Added to supply what is needed; additional; being, or serving as, a supplement; as, a supplemental law; a supplementary sheet or volume.
Thesaurus Entries
accessory, accidental, added, additional, adjunct, adscititious, adventitious, ancillary, annexed, another, appended, appurtenant, ascititious, attached, auxiliary, casual, circumstantial, collateral, contingent, contributory, excess, extra, extraneous, farther, fortuitous, fresh, further, incidental, inessential, more, new, nonessential, other, plus, secondary, spare, subordinate, subsidiary, superadded, superfluous, supernumerary, supervenient, supplemental, supportive, surplus, ulterior, unessential
