This is the 424th most frequent Bulgarian word.
българската
"Българската" means "the Bulgarian" (feminine singular or definite form).
The word 'българската' is used here as an adjective meaning 'Bulgarian', agreeing in gender and number with the noun 'природа', which is feminine singular.
Обожавам българската природа.
I adore the Bulgarian nature.
In this sentence, 'българската' qualifies the noun 'култура', indicating possession or association with Bulgaria.
Това е част от българската култура.
This is part of the Bulgarian culture.
Here, 'българската' describes 'литература', again agreeing in gender and number, emphasizing the relationship to Bulgaria.