What does "complementary colors" mean?

Complementary colors are pairs of colors that are opposite one another on the color wheel, according to Tiger Color. These colors are highly contrasting and, when mixed together in the right proportions, create a neutral color – gray if they are tints, or white if they are light.

When working with the primary colors blue, yellow and red, the complementary color to each can be made by mixing the other two primary colors. The three traditional complementary color pairings are red with green, blue with orange and yellow with violet. These high-contrast color pairs are frequently used in advertising, art and decorative color schemes to make colors brighter and to highlight specific items or words.