This is the 10835th most frequent Polish word.
dziewczynami
"Dziewczynami" means "girls" in the instrumental plural form in Polish.
The word 'dziewczynami' is used here in its instrumental plural form to denote 'with the girls' as part of a prepositional phrase.
Spacerowałem z dziewczynami po parku.
I was walking with the girls in the park.
In this sentence, 'dziewczynami' is again in its instrumental plural form, used to indicate 'with the girls' in the context of the activity.
Dzielę opinie z dziewczynami podczas spotkania.
I share opinions with the girls during the meeting.
Here, 'dziewczynami' functions in the instrumental plural form, specifying the group 'with the girls' in an accompanying role for the action.