This is the 1948th most frequent Polish word.
brata
"Brata" means "brother" in the accusative or genitive case in Polish.
The word 'brata' is in the accusative case (kogo? co?), used here because it's the direct object of the verb 'widzę' (I see).
Widzę mojego brata na dworze.
I see my brother outside.
'Brata' is again in the accusative case due to its role as the direct object of the verb 'znaleźć' (find).
Nie mogę znaleźć brata.
I cannot find my brother.
In this example, 'brata' is in the genitive case (kogo? czego?) due to the verb 'słuchać' (to listen to), which requires the genitive case in Polish.