This is the 9479th most frequent Russian word.
улицу
The Russian word "улицу" means "street" (accusative case).
The word 'улицу' is in the accusative case, indicating the direct object of the verb 'перешёл' (crossed).
Я перешёл улицу.
I crossed the street.
The word 'улице' is in the prepositional case, following the preposition 'по', describing the location of the action.
Мы прогуливались по улице.
We were strolling along the street.
The word 'улица' is in the nominative case, used as the subject of the sentence.