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

Etymology

Origin of supplementary

First recorded in 1660–70; supplement + -ary

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

Combined, the fiscal 2025 supplementary budget and this year’s regular spending came to about ¥141 trillion, meaning that the ministries’ requests represent an increase of about ¥2.5 trillion.

From The Wall Street Journal ● Sep. 4, 2026

It was the first time a Welsh government has lost a vote on a supplementary budget - which is in addition to the main budget exercise that happens in the autumn.

From BBC ● Aug. 26, 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

Not a hard left turn, but a supplementary detail to take with us in the end.

From Salon ● Jun. 15, 2026

This setback had not put a damper on his Himalayan career, however: he’d gone on to climb K2, Lhotse, Cho Oyu, Ama Dablam, and, in 1993, Everest without supplementary oxygen.

From "Into Thin Air" by Jon Krakauer

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

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

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

At once a storm of "supplementaries" broke forth.

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

Related Words

• ancillary
• auxiliary
• increased