This is the 6877th most frequent Turkish word.
bulgaristan
Bulgaria.
'Bulgaristan' in this sentence is used as the proper noun name of the country.
Bulgaristan, Doğu Avrupa'da bir ülkedir.
Bulgaria is a country in Eastern Europe.
'Bulgaristan' here plays the role of indicating origin, implying something—foods—is from Bulgaria.
Bulgaristan'dan gelen yemekler çok lezzetlidir.
The foods from Bulgaria are very tasty.
In this sentence, 'Bulgaristan' is the object of the verb 'visited', referring to the place visited.