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

The campaign was created to help ease the financial strain associated with her care, including treatment costs, complementary therapies, travel to medical appointments and everyday living expenses. —Angelique Brenes, PEOPLE, 1 May 2026

No space is complete without a complementary playlist. —Claire Hoppe Norgaard, Better Homes & Gardens, 1 May 2026

The contrast underscores the complementary goals of the missions. —Samantha Mathewson, Space.com, 1 May 2026

Mindfulness is now widely advocated as a component of psychotherapy and as an element of complementary and alternative medicine. —Charles Preston, Encyclopedia Britannica, 30 Apr. 2026

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