This is the 7063rd most frequent Russian word.
белогоровкой
"Белогоровкой" is the instrumental case of "Белогоровка," a proper noun typically referring to a geographic location or settlement named Belogorovka in Russia or Ukraine.
Here, 'белогоровкой' is used as an adjective describing the characteristic name of the meadow, indicating its association with the name 'Belogorovka'.
Я гулял по красивой белогоровкой поляне.
I walked in the beautiful meadow of Belogorovka.
In this instance, 'белогоровкой' describes the road, specifying that the road is associated with 'Belogorovka'.
По белогоровкой дороге мы добрались до деревни.
We arrived at the village via the road of Belogorovka.
Here, 'белогоровкой' attributes the forest to 'Belogorovka', functioning as a specific modifier for the noun forest and denoting its relationship to the locality of Belogorovka.