Makhachkala (məkhächˌkəläˈ) [key], city (1989 pop. 317,000), capital of Dagestan Republic, SE European Russia, a port on the Caspian Sea. It is an important commercial and industrial center with oil refineries that are linked by pipeline with the Grozny fields. Machinery and textiles are manufactured. Founded in 1844 as a Russian stronghold, the city, called Petrovsk, was renamed Makhachkala in 1921.