This is the 8917th most frequent Russian word.
псковское
"Pskovskoye" means "related to Pskov," a city or region in Russia.
The word 'псковское' is used as an adjective to describe the origin of the jam, indicating that it comes from Pskov.
Я купила псковское варенье, сделанное из местных ягод.
I bought Pskov jam made from local berries.
Here, 'псковское' acts as an adjective attributing the lake to the region or location of Pskov.
Псковское озеро привлекает туристов своей красотой.
Pskov Lake attracts tourists with its beauty.
In this sentence, 'псковское' conveys a characteristic or essence of Pskov as an adjective.