This is the 3612th most frequent Polish word.
dzieci
Children.
Here, "dzieci" is the plural noun meaning "children", used as the subject of the sentence.
Dzieci bawią się w ogrodzie.
The children are playing in the garden.
In this sentence, "dzieci" is the recipient or beneficiaries of the action, in the dative case.
Mama przygotowuje obiad dla dzieci.
The mother is preparing lunch for the children.
Here, "dzieci" functions as a direct object and is in the accusative case.