Kolomna (kəlômˈnə) [key], city (1990 pop. 163,000), central European Russia, at the confluence of the Moskva and Oka rivers. Locomotives and synthetic rubber are produced. Known in 1177, the city became a Muscovite outpost in 1301 and has been an industrial center since 1863. Remains of the towers of Kolomna's 16th-century kremlin are still standing.