Etymology From complement + -ary. Piecewise doublet of complimentary.
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Acting as a complement; making up a whole with something else.
I'll provide you with some complementary notes to help you study.
The two business partners had complementary abilities: one had excellent people skills, while the other had a head for figures.
1 more example
Using the terminology we introduced earlier, we might then say that black and white squares are in complementary distribution on a chessboard. By this we mean two things: firstly, black squares and white squares occupy different positions on the board: and secondly, the black and white squares complement each other in the sense that the black squares together with the white squares comprise the total set of 64 squares found on the board (i.e. there is no square on the board which is not either black or white).1988, Andrew Radford, Transformational grammar: a first course, Cambridge, UK: Cambridge University Press, page 140:
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Biology, Genetics, Medicine, Natural sciences, Sciences Of the specific pairings of the bases in DNA and RNA.
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Natural sciences, Physical sciences, Physics Pertaining to pairs of properties in quantum mechanics that are inversely related to each other, such as speed and position, or energy and time. (See also Heisenberg uncertainty principle.)
the hands of the most skilful and cunning complementaries alive1600 (first performance), Beniamin Ionson [i.e., Ben Jonson], “Cynthias Reuels, or The Fountayne of Selfe-Loue. […]”, in The Workes of Beniamin Ionson (First Folio), London: […] Will[iam] Stansby, published 1616, →OCLC:
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An angle which adds with another to equal 90 degrees.