complementary

from WordNet (r) 3.0 (2006)

complementary
    adj 1: of words or propositions so related that each is the
           negation of the other; "`male' and `female' are
           complementary terms"
    2: acting as or providing a complement (something that completes
       the whole) [syn: {complemental}, {complementary},
       {completing}]
    n 1: 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" [syn:
         {complementary color}, {complementary}]

from The Collaborative International Dictionary of English v.0.48

Complementary \Com`ple*men"ta*ry\, a.
   Serving to fill out or to complete; as, complementary
   numbers.
   [1913 Webster]

   {Complementary colors}. See under {Color}.

   {Complementary angles} (Math.), two angles whose sum is
      90[deg].
      [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Complementary \Com`ple*men"ta*ry\, n. [See {Complimentary}.]
   One skilled in compliments. [Obs.] --B. Jonson.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

21 Moby Thesaurus words for "complementary":
      analogous, answering, coequal, complemental, completing,
      completive, completory, consummative, consummatory, correspondent,
      corresponding, culminative, equipollent, equivalent, filling,
      fulfilling, homologous, perfective, reciprocal, reciprocative,
      tantamount