Ostrovu
Ostrovu is a term that can refer to several different things, primarily place names or related concepts in Slavic languages. The word itself, "ostrov" (остров), directly translates to "island" in Russian and many other Slavic languages. Therefore, "ostrovu" often appears as a grammatical case form of "ostrov," indicating possession or location related to an island, or as part of a proper noun that includes the word for island.
Several geographical locations bear names incorporating this root. For example, Ostrov is a town in Pskov Oblast,