supplementary

American  

[suhp-luh-men-tuh-ree] / ˌsʌp ləˈmɛn tə ri /

adjective

1. Also of the nature of or forming a supplement; additional.

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noun

• supplementaries
  plural

1. a person or thing that is supplementary.

supplementary British  

/ ˌsʌplɪˈmɛntərɪ, -trɪ /

adjective

1. Also (less commonly): supplemental. forming or acting as a supplement

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noun

1. a person or thing that is a supplement

Other Word Forms

Derived Forms

• nonsupplementary
  adjective
• presupplementary
  adjective
• unsupplementary
  adjective
• supplementarily
  adverb

Inflected Forms

Nouns

• supplementaries
  plural

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Etymology

Origin of supplementary

First recorded in 1660–70; supplement + -ary

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Explanation

Supplementary is a little something extra to fill in a gap, like when your teacher suggests supplementary reading material that you may or may not get around to checking out. Supplementary can be an important part of something or just extra support. The word supplement comes from the Latin supplementum for "something added to fix a deficiency" and the suffix -ary means "connected with." Put them together and you have something connected with filling in. The supplementary support of digging a moat around your sand castle might save it from a wave, but that supplementary reading on your syllabus isn't required (although it might save your grade).

Example Sentences

See Examples For:

supplementary supplementaries

Interest rates for the PBOC’s pledged supplementary lending will be lowered by 0.25 percentage points to 1.5%, in a bid to better support the real economy, said the PBOC.

From The Wall Street Journal ● Sep. 29, 2026

It is not as if they need the supplementary income streams.

From BBC ● Sep. 16, 2026

“I’ve been training a little bit more, doing just supplementary things to be able to make sure that I’m in a good place,” Ohtani said after returning to the lineup Monday.

From Los Angeles Times ● Sep. 9, 2026

When we offer supplementary food, such as seeds or meat scraps, this attracts birds of many different species in a combination and number that would not happen in nature.

From Science Daily ● Aug. 24, 2026

The nets were designed to leach condensation out of the cool night air, and were an important supplementary source of water in the Elmuthaleth.

From "Strange the Dreamer" by Laini Taylor

The storm of "supplementaries" showed no sign of abating, until the SPEAKER, who rarely fails to find the appropriate phrase, remarked upon "This thirst for information," and so dissolved the House in laughter.

From Punch, or the London Charivari, Volume 153, July 11, 1917 by Various

At once a storm of "supplementaries" broke forth.

From Punch, or the London Charivari, Volume 153, July 18, 1917 by Various

There were other garments and supplementaries, all treated in the same way.

From A Woman-Hater by Charles Reade

While he fretted his still pounding head, Bill rode the round-up of registers, supplementaries and totals.

From A Canadian Bankclerk by J. P. Buschlen

A long question to the Board of Trade, on the subject of horse-hides, followed by a series of supplementaries delivered with his customary emphasis, showed that he is not yet resigned to his muzzle.

From Punch, or the London Charivari, Volume 153, August 22, 1917 by Various

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Related Words

• ancillary
• auxiliary
• increased

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