This is the 9066th most frequent Russian word.
румынию
"Румынию" is the accusative form of "Румыния," which means "Romania" (a country).
In this sentence, ‘Румынию’ is utilized in the accusative case for the direct object of the verb 'посетил'.
Мой лучший друг посетил Румынию в прошлом году.
My best friend visited Romania last year.
This sentence demonstrates ‘Румынию’ in the accusative case as it is the object of the verb 'изучаем'.
Мы изучаем культуру Румынию и её историю.
We study the culture of Romania and its history.
Here, 'Румынию' is in the accusative case as it indicates the destination of the travel.