complementary colour
noun /ˌkɒmplɪmentri ˈkʌlə(r)/
/ˌkɑːmplɪmentri ˈkʌlər/
(US English complementary color)
(specialist)- a colour that, when mixed with another colour, gives black or white
- a colour that gives the greatest contrast when combined with a particular colour
- The designer has chosen the complementary colours blue and orange.