Complementair

Complementair is a Dutch adjective meaning complementary, or providing what completes something else. It is used to describe a relationship in which two or more elements together form a coherent whole, or where one element fills a gap left by another. The term appears across disciplines, with nuances that depend on the field of application.

Etymology and usage. The word comes from French complémentaire, via Latin complementarius, indicating something that completes. In color theory, complementaire kleuren refers to pairs of colors that are opposite on the color wheel and create high contrast when used together. In mathematics and logic, the concept of a complement describes what remains outside a given set within a universal context; in probability, the complement of an event is what does not occur. In linguistics and phonology, complementary distribution describes a situation where two sounds never occur in the same phonetic environment. In economics and business, complementary goods are products that are commonly used together, so demand for one influences demand for the other. In nutrition, complementary proteins are plant-based foods that, when eaten in combination, provide a complete set of essential amino acids.

Examples. A design team may pair a bold primary color with its complement to achieve visual tension. A retailer might market complementary product lines to encourage cross-selling. In planning, complementary skill sets can cover different parts of a project.

See also. Complement, complementary colors, complementary goods, complementarity.