What does borshkov mean in Russian?

There seems to be a slight misspelling. Borshchov is likely the word you're looking for, and it's the plural form of "borsch" in Russian.

Borsh (борщ) is a popular Russian soup, often made with beets, cabbage, potatoes, and other vegetables.

So, "borshchov" means "borsches". It would be used to refer to multiple bowls of borsh or different varieties of the soup.