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.
Related Words
See appendix. See complement.
Other Word Forms
- supplementation noun
- supplementer noun
- unsupplemented adjective
- well-supplemented adjective
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”; full 1 ) + -mentum -ment
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.
In addition, an annual supplement of £440 should be paid on cars with a list price of more than £40,000, or £50,000 for EVs.
From BBC • Mar. 31, 2026
“The inclusion of a maiden resource for West Dome Underground and extensions at Main Dome Underground outline exciting high-grade additions which can serve as a supplement to the base load low-grade open pit,” says Hissey.
From The Wall Street Journal • Mar. 30, 2026
In the kitchen, dozens of supplement bottles line the countertop, each promising a different type of nutritional benefit.
From Slate • Mar. 30, 2026
However, they too can sometimes produce errors, making it necessary to supplement their findings with additional evidence such as open-source data.
From Barron's • Mar. 30, 2026
A draught of cooks, from every inn and eating-house for miles around, arrived to supplement the dwarves and other odd folk that were quartered at Bag End.
From "The Fellowship of the Ring" by J.R.R. Tolkien
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.
