[ kom-pluh-men-tuh-ree, -tree ]
/ ˌkɒm pləˈmɛn tə ri, -tri /
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forming a complement; completing.
complementing each other.
noun, plural com·ple·men·ta·ries.
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IS and ARE are both forms of which verb?

Origin of complementary

First recorded in 1590–1600; complement + -ary

OTHER WORDS FROM complementary

com·ple·men·ta·ri·ness, nounun·com·ple·men·ta·ry, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


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.

Quiz yourself on complementary vs. complimentary!

Should complementary or complimentary be used in the following sentence?

My comment was meant to be _____—I really do like your shoes!

How to use complementary in a sentence

British Dictionary definitions for complementary



/ (ˌkɒmplɪˈmɛntərɪ, -trɪ) /

acting as or forming a complement; completing
forming a satisfactory or balanced whole
forming a mathematical complementsine and cosine are complementary functions
maths logic (of a pair of sets, etc) mutually exclusive and exhaustive, each being the complement of the other
(of genes) producing an effect in association with other genes
involving or using the treatments and techniques of complementary medicine

Derived forms of complementary

complementarily or complementally, adverbcomplementariness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012