This is the 3328th most frequent Polish word.
ulicą
"Ulicą" means "street" (instrumental case) in English.
The word 'ulicą' is used here in the instrumental case, indicating the means or adjacency by/along which the action ('strolling') is taking place.
Chodziliśmy wzdłuż ulicą, podziwiając widoki.
We strolled along the street, admiring the views.
In this sentence, 'ulicą' also appears in the instrumental case, defining the path or medium ('the street') through which the subject ('car') is acting ('driving').
Samochód jechał ulicą bardzo szybko.
The car was driving on the street very quickly.
Here, 'ulicą' serves as part of a descriptive phrase in the instrumental case, emphasizing its characteristic relation to the described 'apartment' and its location.