This is the 13576th most frequent Polish word.
piwa
The Polish word "piwa" means "beers" (plural of "piwo").
'Piwa' is used here in its plural genitive form, indicating 'beers' as an uncountable noun in terms of quantity.
Kupiłem kilka piwa na wieczór.
I bought some beer for the evening.
Here, 'piwa' is in genitive singular form, modifying 'to' to express possession or describe the beer.
To piwa jest bardzo smaczne.
This beer is very tasty.
'Piwa' takes the genitive singular form here due to the prepositional phrase indicating dislike.