com·ple·men·ta·tion /ˌkɑmplə(ˌ)mɛnˈteʃən, mən-/
  complementation
       n 1: the grammatical relation of a word or phrase to a predicate
       2: (linguistics) a distribution of related speech sounds or
          forms in such a way that they only appear in different
          contexts [syn: complementary distribution]