supplement
Americannoun
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something added to complete a thing, supply a deficiency, or reinforce or extend a whole.
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a part added to a book, document, etc., to supply additional or later information, correct errors, or the like.
- Synonyms:
- postscript, epilogue, addendum
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a part, usually of special character, issued as an additional feature of a newspaper or other periodical.
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Geometry. the quantity by which an angle or an arc falls short of 180° or a semicircle.
verb (used with object)
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to complete, add to, or extend by a supplement.
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to form a supplement or addition to.
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to supply (a deficiency).
noun
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an addition designed to complete, make up for a deficiency, etc
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a section appended to a publication to supply further information, correct errors, etc
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a magazine or section inserted into a newspaper or periodical, such as one with colour photographs issued every week
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geometry
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either of a pair of angles whose sum is 180°
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Abbreviation: sup. supp. an arc of a circle that when added to another arc forms a semicircle
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verb
Usage
What does supplement mean? A supplement is an addition to something that completes it or makes up for a shortcoming, as in He takes vitamin supplements to make up for his vitamin C deficiency. A supplement is also an addition to a book that provides important information or corrects errors. In this sense, supplement can be confused with the words appendix and index. An appendix gives additional information, such as charts and graphs, but the book or document would be considered complete without it. An index is an alphabetical list of names or topics with page numbers that helps you find something specific in the book, such as all the references to John Wilkes Booth in a biography of Abraham Lincoln. As a verb, supplement means to add to something, as in Tameka sold paintings to supplement her income. In this sense, supplement can be confused with the word complement. Both words mean to add something, but to complement means to add something to make up for a missing piece or element, while to supplement is to add extra information. Example: The company built a new roller coaster to supplement its original roller coaster, which always has a long line.
Synonym Usage
See appendix. See complement.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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supplementsimple
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supplementssimple
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have supplementedperfect
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has supplementedperfect
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am supplementingprogressive
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are supplementingprogressive
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is supplementingprogressive
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have been supplementingperfect progressive
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has been supplementingperfect progressive
Past
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supplementedsimple
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had supplementedperfect
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was supplementingprogressive
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were supplementingprogressive
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had been supplementingperfect progressive
Future
Etymology
Origin of supplement
First recorded in 1350–1400; Middle English, from Latin supplēmentum “that by which anything is made full,” equivalent to sup- sup- + plē- (stem of plēre “to fill”; see full 1) + -mentum -ment
Explanation
A supplement is something added to something else. Nutritional supplements add vitamins and minerals to the ones already included in the food you eat. If a zombie army wants to increase its ranks but is running out of bodies, it might supplement its troops with mummies. If the zombies put out their manifesto and then realize they left out an important point, they might supplement the manifesto with a press release. That press release could also be referred to as a supplement.
Vocabulary lists containing supplement
Richard Nixon's "Checkers" Speech (1952)
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Nutrition - Introductory
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Nutrition - Middle School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Only 3.6% of participants taking the supplement left the study, compared with 21% of those in the physiotherapy group.
From Science Daily ● Jul. 25, 2026
The superintendent himself served as the master of ceremonies, with performers weaving around him, cameos by celebrities, and slide projections and film sequences appearing on cue to supplement his applause and laugh lines.
From Los Angeles Times ● Jul. 21, 2026
Their findings suggest that taking a daily spermidine supplement improved several measures of immune response following COVID-19 vaccination.
From Science Daily ● Jul. 21, 2026
Instead, the conversation turns to the longevity industrial complex—biological-age testing, sleep scores, continuous glucose monitors, elaborate supplement stacks.
From The Wall Street Journal ● Jul. 18, 2026
He rigged a block and tackle to supplement a dead tree limb that they were using as a lever.
From "Redwall" by Brian Jacques
But having a strong farm system supplements big spending.
From Los Angeles Times ● Jul. 27, 2026
Three years ago, the FDA placed restrictions on 14 peptides over safety risks, meaning they now fall somewhere between the unregulated world of supplements and the highly structured process of testing new drugs.
From MarketWatch ● Jul. 23, 2026
Johnson's content - followed by more than six million people - drives his followers back to his website, Blueprint, where he sells supplements.
From BBC ● Jul. 11, 2026
Jimenez, the mother of twin girls, says she makes herself feel better by drinking herbal teas and taking herbal liquid supplements.
From The Wall Street Journal ● Jul. 10, 2026
His mother works at the Bucks County Courier Times, feeding advertising supplements into a “big giant machine” that inserts them into the newspapers that get delivered to homes.
From "Drama High" by Michael Sokolove
Portland supplemented the federal construction money with local dollars, creating incentives that were hard to turn down.
From Salon ● Jul. 4, 2026
Troha then gave another group of mice chow supplemented with methionine.
From Science Daily ● Jun. 1, 2026
Mejia has reported raising $143,000 for his reelection campaign, according to his latest campaign finance statement, which has been supplemented by nearly $500,000 from the city’s matching funds program.
From Los Angeles Times ● May 29, 2026
Its sales are now supplemented by mNexspike, a next-generation vaccine designed for the current respiratory virus season.
From Barron's ● May 13, 2026
The gym instructor was a short, chunky man in his early thirties who taught in the mornings in a nearby public high school and supplemented his income by teaching in our yeshiva during the afternoons.
From "The Chosen" by Chaim Potok
Rather than replacing existing recommendations, Dr. Macdonald suggests supplementing them with guidance focused on what he calls "optimal health outcomes."
From Science Daily ● Jun. 23, 2026
Proponents said it can elevate instruction, narrow the digital divide, help pupils with language barriers and other needs—while often supplementing, not replacing, core curriculum.
From The Wall Street Journal ● Jun. 21, 2026
But some experts suggest the solar-powered streetlights are best suited to supplementing large data centres, not replacing them: there will still be a need for their concentrated computing power and efficiencies of scale.
From BBC ● May 1, 2026
“As the portfolio refreshes, that capital will start earning the current interest rate, and that is supplementing their growth,” Nygren says.
From MarketWatch ● Feb. 5, 2026
I wondered if maybe he was an actor supplementing his income.
From "Looking for Alaska" by John Green
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
