complementary

adjective

com·​ple·​men·​ta·​ry ˌkäm-plə-ˈmen-t(ə-)rē 

1

: serving to fill out or complete

… their economies are more complementary than competitive …

—William Petersen

2

: mutually supplying each other's lack

… the complementary relationship that binds the two.

—Colin S. Gray

3

: relating to or constituting one of a pair of contrasting colors that produce a neutral color when combined in suitable proportions

4

: being complements of each other

complementary acute angles

5

: characterized by the capacity for precise pairing of purine and pyrimidine bases between strands of DNA and sometimes RNA such that the structure of one strand determines the other

6

: of, relating to, or based on complementary medicine

Cancer, for example, might be treated by blending the best of the Western medicine … with complementary approaches that could include … acupuncture, nutrition, herbs and massage.

—Julie Deardorff

complementarily

ˌkäm-plə-ˈmen-t(ə-)rə-lē 

-(ˌ)men-ˈter-ə-lē, 

-ˈta-rə-

adverb

complementariness

ˌkäm-plə-ˈmen-t(ə-)rē-nəs 

noun

complementary noun

Synonyms of complementary

• supplementary
• reciprocal
• mutual

Examples of complementary in a Sentence

… hot and sour soup encapsulates the Taoist principle central to Chinese culture: yin and yang, the notion of balancing the universe's opposing yet complementary forces. —Rebecca Hays, Cook's Illustrated, January & February 2006

Once Austin got used to what he had on, Jerry was going to talk him into a neck scarf of complementary colors and a cream pullover. —Alice Munro, Atlantic, January 1990

Vann and Ellsberg were the odd couple, difficult men from different worlds satisfying complementary needs in each other. —Neil Sheehan, A Bright Shining Lie, 1988

… it was becoming more and more clear to him that Miss Bart herself possessed precisely the complementary qualities needed to round off his social personality. —Edith Wharton, The House of Mirth, 1905

She wore a new outfit with a complementary scarf.

My spouse and I have complementary goals.

Recent Examples on the Web

Each offers something complementary to the season. —Adam Hurly, Robb Report, 17 Dec. 2025

These pocket-sized theaters are built on a distinct but familiar small-business foundation with a complementary cultural philosophy at their core. —Alison Foreman, IndieWire, 16 Dec. 2025

If the committee’s schedule plan earns NCAA approval, having the MLS move in sync will create complementary growth and marketing opportunities for college soccer and the sport as a whole, NextGen committee chair Dan Helfrich said in an interview. —Luke Cyphers, Sportico.com, 12 Dec. 2025

The following night, Allen and Steinfeld stepped out for the Miu Miu afterparty in complementary khaki outfits after attending the designer's show earlier in the day. —Rebecca Aizin, PEOPLE, 12 Dec. 2025

Word History

Etymology

complement entry 1 + -ary entry 2, probably in part after French complémentaire

First Known Use

1829, in the meaning defined at sense 3

Phrases Containing complementary

• complementary angles
• complementary color
• complementary medicine

Rhymes for complementary

• elementary
• entry
• gentry
• sentry

Kids Definition

complementary

adjective

com·​ple·​men·​ta·​ry ˌkäm-plə-ˈment-ə-rē 

-ˈmen-trē

: forming or serving as a complement

Medical Definition

complementary

adjective

com·​ple·​men·​ta·​ry ˌkäm-plə-ˈment-ə-rē, -ˈmen-trē 

1

: relating to or constituting one of a pair of contrasting colors that produce a neutral color when combined in suitable proportions

2

: characterized by molecular complementarity

especially : characterized by the capacity for precise pairing of purine and pyrimidine bases between strands of DNA and sometimes RNA such that the structure of one strand determines the other

complementarily

-ˈmen-trə-lē, -(ˌ)men-ˈter-ə-lē, -ˈment-ə-rə-lē 

adverb

complementariness

-ˈment-ə-rē-nəs, -ˈmen-trē- 

noun