say it: kahm-pluh-MEN-tree
complementary is an adjective and noun meaning "of words or propositions so related that each is the negation of the other". It carries 3 recorded senses.
of words or propositions so related that each is the negation of the other
“`male' and `female' are complementary terms”
acting as or providing a complement (something that completes the whole)
either one of two chromatic colors that when mixed together give white (in the case of lights) or grey (in the case of pigments)
“yellow and blue are complementaries”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for complementary come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.