Duratec is a brand name of the Ford Motor Company used for its gasoline-powered four-cylinder, five-cylinder and six-cylinder passenger car engines.
The Duratec name originally described the family of V6 engines introduced in 1993 in the Ford Mondeo, and in 2000, the four-cylinder engines in the Mondeo became part of the Duratec family. Over time, Duratec was expanded to become an omnibus name for Ford's gasoline engines unrelated to the Mondeo V6, such as the Ford Zeta engine and Ford's variant of the Mazda L engine.
The ambiguous use of the Duratec name is similar to Ford's use of the Duratorq name for diesel engines and EcoBoost for turbocharged gasoline engines.
References
Ford Duratec engine Wikipedia(Text) CC BY-SA