A detinets or detinetz is an ancient Rus' city-fort or central fortified part of a city, similar to the meaning of kremlin or citadel. The term was used in many regions, including: Kievan Rus', Chernihiv, Novgorod, and Kyiv. Old Russian manuscripts mention detinets in various places of Kievan Rus' since the end of the 11th century. From the 13th to the 14th century, detinets were used only in the Russian Pskov-Novgorod region. The origin of the term is uncertain. Some derive it from the Old East Slavic word deti—"children", suggesting it was used to hide children and other less able people during a siege. Polish philologist Lucyjan Malinowski derives the similarly sounding Polish term dziedziniec–"courtyard", from detinets.