complementary (2009-09-10)

Part of Speech: adjective

Pronunciation: ['kahm-plê-'ment-tê-ri]

Definition: Serving to complete or make perfect; of two or more things, serving to compensate for each other's deficiencies.

Usage: We all know couples who complement each other perfectly: "They're a complementary pair—he's rude and she's apologetic." Much of the art of cookery lies in finding tasty complements: "She paid me a compliment by saying that my choice of wines complemented the menu perfectly."

Suggested Usage: Be careful not to confuse the spelling of this word with another that sounds exactly the same: "complimentary," which describes an act of courtesy or praise. "Complementary medicine" is intended to compensate for some of the deficiencies of mainstream medicine. "Complimentary medicine" would merely involve saying nice things about the patient's disease. Something that is complementary is a "complement," it behaves "complementarily" and it exhibits "complementarity." Another, complementary, chain of adjective, adverb and noun exists in the form of "complemental," "complementally" and "complementalness." And finally, the verb: complementary things are said to "complement" each other.

Etymology: From the Latin complementum, "that which fills up or completes," from the verb complere "to fill up, fulfill or complete." Complere is, of course, the origin of our word "complete." Both complementum and complere acquired different meanings when they passed into Spanish and Italian, when the sense of "fulfilling" became dominant - in particular they were used to indicate a fulfillment of the requirements of courteous behavior. When they arrived in English via this circuitous route, they gave us "compliment" and "comply."