This is the 3474th most frequent Polish word.
zimę
The Polish word "zimę" means "winter" (accusative or singular form).
In this sentence, 'zimę' is the accusative form of the noun 'zima' (winter), used because it is the direct object of the verb 'zaczyna się' (starts).
W Polsce zimę zaczyna się często już w listopadzie.
In Poland, winter often starts already in November.
Here, 'zimę' is again in the accusative case as it is the direct object of the verb 'lubię' (I like).
Lubię zimę, ponieważ jest piękna i spokojna.
I like winter because it is beautiful and calm.
In this example, 'zimę' is the accusative form and serves as the direct object of the verb 'pamiętam' (I remember).