Main Entry: com·ple·men·tar·i·ty

Pronunciation: \ˌkäm-plə-(ˌ)men-ˈter-ə-tē, -mən-, -ˈta-rə-\

Function: noun

Date: 1911

1 : the quality or state of being complementary
2 : the complementary relationship of theories explaining the nature of light or other quantized radiation in terms of both electromagnetic waves and particles