complementary
Americanadjective
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acting as or forming a complement; completing
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forming a satisfactory or balanced whole
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forming a mathematical complement
sine and cosine are complementary functions
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maths logic (of a pair of sets, etc) mutually exclusive and exhaustive, each being the complement of the other
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(of genes) producing an effect in association with other genes
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involving or using the treatments and techniques of complementary medicine
Usage
What’s the difference between complementary and complimentary? Complementary is an adjective used to describe something that complements something else—goes along with it and serves to make it better or complete it (as in complementary colors). Complimentary is an adjective that can describe something intended to be a compliment—a comment that expresses praise or admiration of someone (as in a complimentary remark). It can also be used to mean that something is given for free, as in I hope we get complimentary snacks on this flight. Since the primary senses of both words are generally used in positive contexts, it can be easy to confuse them. The easiest way to remember the difference is that complementary often involves something that completes something else, and complete also starts with c-o-m-p-l-e. On the other hand, you can remember that complimentary is spelled with an i because compliments are something that I like to get (and give). Nice shirt, by the way. Here’s an example of complementary and complimentary used correctly in the same sentence. Example: Sometimes, when the chef overhears complimentary feedback about a dish, she sends out a complimentary bottle of wine—one that’s complementary to the rest of the meal, of course. Want to learn more? Read about the difference between compliment and complement.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of complementary
First recorded in 1590–1600; complement + -ary
Explanation
If something is complementary, then it somehow completes or enhances the qualities of something else. If your beautiful voice is completely complementary to your brother's song writing skills, you should form a family band! You’ve probably heard of “complementary colors,” colors that are opposite in hue on the color wheel but actually go well together. When combined, they make a harmonious palette. People’s personalities can also be complementary, as can certain food pairings. But be careful not to confuse this adjective with the closely spelled complimentary, which means “supplied free of charge.”
Vocabulary lists containing complementary
The Hidden Oracle
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The Night Circus
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"The Hunger Games" Vocabulary from Chapter 5
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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:
Throughout the day, fans crossed the grounds in bright Latin American soccer jerseys, the eye-catching complementary greens and reds of Mexico and the rich blue of El Salvador dotting the crowd.
From Los Angeles Times ● Aug. 4, 2026
Bernstein analysts said in a separate note that the two companies had complementary portfolios in oncology and cardiovascular diseases, but that a deal seemed unlikely to go ahead.
From The Wall Street Journal ● Aug. 3, 2026
Each pathway filled a different combination of energy levels within zinc-70, allowing researchers to observe its nuclear structure from two complementary perspectives.
From Science Daily ● Jul. 31, 2026
Dr Yasir Ali, a reader in Transport Modelling at Loughborough University, says e-scooters are "complementary" to other modes of transport, rather than replacing them.
From BBC ● Jul. 22, 2026
The overwhelming biological merits of a self- complementary DNA molecule made him effectively concede the race.
From "Double Helix" by James D. Watson
But just as much as complementaries, van Gogh loved using colors that are adjacent on the color wheel.
From Washington Post ● Mar. 12, 2019
This novel about young Ged’s education in both magic and self-understanding relies throughout on Taoist notions of complementaries — the balance between light and dark, speech and silence, self and shadow.
From Washington Post ● Oct. 3, 2016
In a similar way, light and dark tints act as complementaries.
From The Science of Human Nature A Psychology for Beginners by William Henry Pyle
If this colour is deep, it gives rise to a luminous complementary, such as orange, or yellow, and enfeebles the black; while the other complementaries, such as violet or green, strengthen and purify it.
From Field's Chromatography or Treatise on Colours and Pigments as Used by Artists by Thomas Salter
Greenish-yellow and blue are a pair of complementaries, as already mentioned.
From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6 "Cockaigne" to "Columbus, Christopher" by Various
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.
