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com·ple·men·ta·ry (kŏmplə-mĕntə-rē, -trē)
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adj.
1. Forming or serving as a complement; completing: finally acquired the complementary volumes that made a whole set.
2. Offsetting mutual deficiencies or enhancing mutual strengths: "Creatures with complementary skills flourish in each other's presence" (Richard Dawkins).
3. Of or relating to complementary medicine.
4. Genetics Of or relating to a group of genes that act in concert to produce a specific phenotype.
5. Biochemistry Of or relating to the specific pairing of the purines and pyrimidines between strands of a DNA or an RNA molecule.
6. Physics Of or relating to the hypothesis that underlying properties of entities, especially subatomic particles, may manifest themselves in mutually exclusive forms at different times, depending on the conditions of the observation, and that any physical model that describes entities in terms of one form or the other will be incomplete.

comple·menta·ri·ly (-tə-rə-lē, -trə-lē, -mĕn-târə-lē) adv.
comple·menta·ri·ness n.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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