This is the 2124th most frequent Polish word.
osiedla
"Osiedla" means "housing estates" or "residential areas" in English.
Here, 'osiedla' means 'housing estates' and is in the plural form, functioning as the subject of the sentence.
Osiedla na przedmieściach szybko się rozwijają.
Housing estates in the suburbs are growing rapidly.
'Osiedla' again means 'housing estates' and is used in the accusative case to indicate the places traversed.
Spaceruję przez osiedla w poszukiwaniu sklepu.
I am walking through the housing estates looking for a shop.
'Osiedla' refers to a specific 'housing estate' and is in the genitive case to show possession in this context.