This is the 2760th most frequent Russian word.
косово
The Russian word "Косово" refers to Kosovo, a region in the Balkans.
Here, 'Косово' is used as a geographical proper noun referring to a specific region or territory.
Косово — это спорная территория в Европе.
Kosovo is a disputed territory in Europe.
'Косово' in this sentence again refers to the region but is used here as the place of origin of the souvenir.
Мой брат из косово привез красивый сувенир.
My brother brought a beautiful souvenir from Kosovo.
In this case, 'косово' refers to slanted or inclined land, showcasing its use in a different, non-proper noun sense.