This is the 110th most frequent Norwegian word.
barn
Child.
In this context, 'barn' is used to denote plural children as a general term.
Jeg skal besøke en venns barn i helgen.
I am going to visit a friend's children this weekend.
In this sentence, 'barnet' is the singular noun form meaning 'the child', used as a subject.
Barnet leker i hagen.
The child is playing in the garden.
Here, 'barna' is the plural form meaning 'the children', indicating multiple individuals.