sup·​ple·​men·​ta·​ry | \ˌsə-plə-ˈmen-tə-rē, -ˈmen-trē\

Definition of supplementary 

1 : added or serving as a supplement : additional supplementary reading

2 : being or relating to a supplement or a supplementary angle

Keep scrolling for more

Synonyms & Antonyms for supplementary


accessorial, accessory, appurtenant, auxiliary, peripheral, supplemental


chief, main, principal

Visit the Thesaurus for More 

Examples of supplementary in a Sentence

a list of supplementary material for the class the teacher's edition of the textbook comes with a lot of supplementary material

Recent Examples on the Web

The United States, however, has not ratified the 1992 Convention on Biological Diversity (CBD), to which the 2010 Nagoya Protocol is a supplementary agreement, and would not be bound by changes to the protocol. Kai Kupferschmidt, Science | AAAS, "Plan to amend biopiracy rules would ‘smother research,’ biologists warn," 3 July 2018 Taxpayers with any items on those supplementary forms—such as student-loan interest or education tax credits—must complete those schedules, too. Richard Rubin, WSJ, "There’s a New 1040 Tax Form. Will Millions of E-Filers Even Notice?," 29 June 2018 Children’s librarians have suggested offering Little House fans the Birchbark series, by American Indian author Louise Erdrich, as either counter-programming or supplementary reading. Constance Grady, Vox, "Laura Ingalls Wilder’s Little House books are beautiful. They are also filled with racism.," 26 June 2018 But there are almost no details about this supplementary DOJ spending, which is not paid for by the permanent, indefinite appropriation for special counsels. Salvador Rizzo, Washington Post, "Fact-checking President Trump’s attacks on the cost of Mueller’s investigation," 4 June 2018 The winning horse can also get whatever supplementary fees to the Derby exceed $900,000. Kelly Ward, The Courier-Journal, "Here are the answers to all of your dumb horse racing questions," 5 June 2018 All of these Capcom collections also include an incredible amount of supplementary material. Andrew Webster, The Verge, "Maybe the Nintendo Switch doesn’t need a virtual console after all," 30 May 2018 Statisticians have also been exploring supplementary data sources, including administrative data. The Economist, "Plunging response rates to household surveys worry policymakers," 24 May 2018 Messner was one of the first two climbers to scale Mount Everest without supplementary oxygen, 40 years ago. Fox News, "Italian, Polish climbers win prestigious Spanish prize," 16 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'supplementary.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of supplementary

1667, in the meaning defined at sense 1

Keep scrolling for more

Learn More about supplementary

Share supplementary

Statistics for supplementary

Look-up Popularity

Time Traveler for supplementary

The first known use of supplementary was in 1667

See more words from the same year

Keep scrolling for more

More Definitions for supplementary


sup·​ple·​men·​ta·​ry | \ˌsə-plə-ˈmen-tə-rē \

Kids Definition of supplementary

: added to something else : additional supplementary income


sup·​ple·​men·​ta·​ry | \ˌsəp-lə-ˈment-ə-rē, -ˈmen-trē \

Medical Definition of supplementary 

: added or serving as a supplement supplementary vitamins


sup·​ple·​men·​ta·​ry | \ˌsə-plə-ˈmen-tə-rē, -trē \

Legal Definition of supplementary 

: added or serving as a supplement

Keep scrolling for more

Comments on supplementary

What made you want to look up supplementary? Please tell us where you read or heard it (including the quote, if possible).


a trusted follower

Get Word of the Day daily email!

Test Your Vocabulary

Difficult Vocab Quiz

  • the-education-of-achilles-eugne-delacroix
  • Which is a synonym of discomfit?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!