Synonyms for Supplementary:

adj.

additional (adjective)
further, extra, completing.
extra (adjective)
in addition, additional, supplemental.
more (adjective)
besides, also.
supplementary (adjective)
auxiliary, added, extra.

n.

in addition, further, besides, together with something, as well, also, too. supplementary (noun)
secondary, subsidiary, additional, supplemental, auxiliary, added.

Other synonyms:

besides, also. too. further. Other relevant words:
further, besides, also, as well, extra, too, in addition, completing.

Usage examples for supplementary

  1. If you will now be so good as to cast your eye over the copy enclosed, what follows the present sentence, will be some details, supplementary to that only, necessary for your information, but not proper for me to state to Mr. Jay. – Memoir, Correspondence, And Miscellanies, From The Papers Of Thomas Jefferson by Thomas Jefferson
  2. Oliver, his Uncle Cyrus, the rector, and honest John Henry, however they may have differed in their views of the universe or of each other, were one at least in accepting the historical dogma of the supplementary being of woman. – Virginia by Ellen Glasgow