a) Moldova: province in the East of Romania b) Republic of Moldova: independent country at the East of Romania. Ethnically, historically and linguistic this country is also a part of Romania but was occupied by Russians after the world war II. In English we say "Moldavia" for the province/region in Romania, and (The Republic of) "Moldova" for the newly founded country.
Moldova is an European country, between Romania and Ukraine. Moldova is not now a part of Russia. Moldova was integrally an historical province of Romania. Note that after the Ribbentrop-Molotov pact (1939) the central-eastern part of Moldova (Basarabia) become a province of Russia and the South eastern part become a part of Ukraine.