[ kom-pluh-men-tuh-ree, -tree ]
See synonyms for complementary on
  1. forming a complement; completing.

  2. complementing each other.

noun,plural com·ple·men·ta·ries.

Origin of complementary

First recorded in 1590–1600; complement + -ary

Other words from complementary

  • com·ple·men·ta·ri·ness, noun
  • un·com·ple·men·ta·ry, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use complementary in a sentence

  • Not, we must again emphasize, not in a hermaphroditic personality, but in two perfect complementaries—mates; not one but a pair.

  • In the same way mix the two complementaries yellow and blue to produce a gray; mix red and green in the same way.

    The Mind and Its Education | George Herbert Betts
  • Cosmic reaction has set in, and union between complementaries is the result.

  • Everything in nature is manifested to us by means of light and its complementaries, reflection and shadow.

  • The greatest possible contrast is that of the complementaries.

    The Painter in Oil | Daniel Burleigh Parkhurst

British Dictionary definitions for complementary



/ (ˌkɒmplɪˈmɛntərɪ, -trɪ) /

  1. acting as or forming a complement; completing

  2. forming a satisfactory or balanced whole

  1. forming a mathematical complement: sine and cosine are complementary functions

  2. maths logic (of a pair of sets, etc) mutually exclusive and exhaustive, each being the complement of the other

  3. (of genes) producing an effect in association with other genes

  4. involving or using the treatments and techniques of complementary medicine

Derived forms of complementary

  • complementarily or complementally, adverb
  • complementariness, 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