This is the 242nd most frequent Polish word.
dziecko
Child.
Here, 'dziecko' is used as a singular noun to denote a young human being (child).
Dziecko bawi się w ogrodzie.
The child is playing in the garden.
In this case, 'dziecko' appears in its plural form 'dzieci', referring to more than one child.
Ona ma dwoje dzieci.
She has two children.
Here, the root of 'dziecko' is used adjectivally in the word 'dziecinne', meaning 'childish', describing activities.